Stabilized ablation systems and methods

ABSTRACT

Surgical systems and methods for administering an ablation treatment and other therapeutic or diagnostic protocols to a patient tissue involve a flexible stabilizer mechanism having an inner recess and an ablation mechanism coupled with the stabilizer mechanism.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/473,311, filed May 16, 2012, entitled “STABILIZED BIPOLAR ABLATIONSYSTEMS AND METHODS,” which is a continuation-in-part (CIP) of U.S.patent application Ser. No. 13/295,852 filed Nov. 14, 2011, entitled“STABILIZED BIPOLAR ABLATION SYSTEMS AND METHODS,” which is anonprovisional claiming the benefit of priority to U.S. ProvisionalPatent Application No. 61/456,918 filed Nov. 12, 2010, entitled“STABILIZED BIPOLAR ABLATION SYSTEMS AND METHODS.” This application isalso related to U.S. patent application Ser. No. 12/124,743 and Ser. No.12/124,766, filed May 21, 2008. The entire content of each of the abovefilings is incorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

Embodiments of the present invention related generally to the field ofmedical devices and methods, and in particular to therapeutic modalitiesinvolving tissue ablation or lesion formation.

There are many instances where it is beneficial to perform a therapeuticintervention in a patient, using a system that is inserted within thepatient's body. One exemplary therapeutic intervention involves theformation of therapeutic lesions in the patient's heart tissue to treatcardiac conditions such as atrial fibrillation, atrial flutter, andarrhythmia. Therapeutic lesions may also be used to treat conditions inother regions of the body including, but not limited to, the prostate,liver, brain, gall bladder, uterus, and other solid organs. Typically,the lesions are formed by ablating tissue with one or more electrodes.Electromagnetic radio frequency (“RF”) energy applied by the electrodeheats and eventually kills or ablates the tissue to form a lesion.During the ablation of soft tissue (e.g. tissue other than blood, boneand connective tissue), tissue coagulation occurs, which leads to tissuedeath. Thus, references to the ablation of soft tissue are typicallyreferences to soft tissue coagulation. “Tissue coagulation” can refer tothe process of cross linking proteins in tissue to cause the tissue tojell. In soft tissue, it is the fluid within the tissue cell membranesthat jells to kill the cells, thereby killing the tissue. Depending onthe procedure, a variety of different electrophysiology devices may beused to position one or more electrodes at the target location.Electrodes can be connected to power supply lines and, in someinstances, the power to the electrodes can be controlled on anelectrode-by-electrode basis. Examples of electrophysiology devicesinclude catheters, surgical probes, and clamps.

Currently known surgical probes which can be used to create lesionsoften include a handle, a relatively short shaft that is from 4 inchesto 18 inches in length and either rigid or relatively stiff, and adistal section that is from 1 inch to 10 inches in length and eithermalleable or somewhat flexible. One or more electrodes are carried bythe distal section. Surgical probes are used in epicardial andendocardial procedures, including open heart procedures and minimallyinvasive procedures where access to the heart is obtained via athoracotomy, thoracostomy or median sternotomy. Exemplary surgicalprobes are disclosed in U.S. Pat. No. 6,142,994, the content of which isincorporated herein by reference.

Clamps, which have a pair of opposable clamp members that may be used tohold a bodily structure or a portion thereof, are used in many typessurgical procedures. Lesion creating electrodes have also been securedto certain types of clamps. Examples of clamps which carry lesioncreating electrodes are discussed in U.S. Pat. No. 6,142,994, and U.S.Patent Publication Nos. 2003/0158549, 2004/0059325, and 2004/024175, thecontents of which are incorporated herein by reference. Such clamps canbe useful when the physician intends to position electrodes on oppositesides of a body structure in a bipolar arrangement.

Atrial fibrillation (AF) can refer to a heart beat rhythm disorder (or“cardiac arrhythmia”) in which the upper chambers of the heart known asthe atria quiver rapidly instead of beating in a steady rhythm. Thisrapid quivering reduces the heart's ability to properly function as apump. AF is a common clinical condition, and presents a substantialmedical issue to aging populations. AF is costly to health systems, andcan cause complications such as thrombo-embolism, heart failure,electrical and structural remodeling of the heart, and even death.Relatedly, AF typically increases the risk of acquiring a number ofpotentially deadly complications, including thrombo-embolic stroke,dilated cardiomyopathy, and congestive heart failure. Quality of life isalso impaired by common AF symptoms such as palpitations, chest pain,dyspnea, fatigue and dizziness. People with AF have, on average, afive-fold increase in morbidity and a two-fold increase in mortalitycompared to people with normal sinus rhythm. One of every six strokes inthe U.S. (some 120,000 per year) occurs in patients with AF, and thecondition is responsible for one-third of all hospitalizations relatedto cardiac rhythm disturbances (over 360,000 per year), resulting inbillions of dollars in annual healthcare expenditures. The likelihood ofdeveloping AF increases dramatically as people age; the disorder isfound in about 1% of the adult population as a whole, and in about 6% ofthose over age 60. By age 80, about 9% of people (one in 11) will haveAF. According to a recent statistical analysis, the prevalence of AF inthe U.S. will more than double by the year 2050, as the proportion ofelderly increases. A recent study called The Anticoagulation and RiskFactors in Atrial Fibrillation (ATRIA) study, published in the Spring of2001 in the Journal of the American Medical Association (JAMA), foundthat 2.3 million U.S. adults currently have AF and this number is likelyto increase over the next 50 years to more than 5.6 million, more thanhalf of whom will be age 80 or over.

As the prevalence of AF increases, so will the number of people whodevelop debilitating or life-threatening complications, such as stroke.According to Framingham Heart Study data, the stroke rate in AF patientsincreases from about 3%/year of those aged 50-59 to more than 7%/year ofthose aged 80 and over. AF is responsible for up to 35% of the strokesthat occur in people older than age 85. Efforts to prevent stroke in AFpatients have so far focused primarily on the use of anticoagulant andantiplatelet drugs, such as warfarin and aspirin. Long-term warfarintherapy is recommended for all AF patients with one or more stroke riskfactors, including all patients over age 75. Studies have shown,however, that warfarin tends to be under prescribed for AF. Despite thefact that warfarin reduces stroke risk by 60% or more, only 40% ofpatients age 65-74 and 20% of patients over age 80 take the medication,and probably fewer than half are on the correct dosage. Patientcompliance with pharmacological intervention such as warfarin isproblematic, and the drug requires vigilant blood monitoring to reducethe risk of bleeding complications.

More recently, the focus has shifted toward surgical or catheterablation options to treat or effect a cure for AF. The ablationtechniques for producing lines of electrical isolation are now replacingthe so-called Maze procedure. The Maze procedure uses a set oftransmural surgical incisions on the atria to create fibrous scars in aprescribed pattern. This procedure was found to be highly efficaciousbut was associated with a high morbidly rate. The more recent approachof making lines of scar tissue with modern ablation technology hasenabled the electrophysiologist or cardiac surgeon to create the linesof scar tissue more safely. Ideally, re-entrant circuits that perpetuateAF can be interrupted by the connected lines of scar tissue, and thegoal of achieving normal sinus rhythm in the heart may be achieved.

Electrophysiologists often classify AF by the “three Ps”: paroxysmal,persistent, or permanent. Paroxysmal AF, typically characterized bysporadic, usually self-limiting episodes lasting less than 48 hours, isusually the most amenable to treatment, while persistent or permanent AFcan be much more resistant to known therapies. Researchers now know thatAF is a self-perpetuating disease and that abnormal atrial rhythms tendto initiate or trigger more abnormal rhythms. Thus, the more episodes apatient experiences and the longer the episodes last, the less chance ofconverting the heart to a persistent normal rhythm, regardless of thetreatment method.

AF is often characterized by circular waves of electrical impulses thattravel across the atria in a continuous cycle, causing the upperchambers of the heart to quiver rapidly. At least six differentlocations in the atria have been identified where these waves cancirculate, a finding that paved the way for maze-type ablationtherapies. More recently, researchers have identified the pulmonaryveins as perhaps the most common area where AF-triggering foci reside.Triggers for intermittent AF and drivers for permanent AF can be locatedat various places on the heart, such as the atria. For example, wheretriggers or drivers are located near the pulmonary veins, it followsthat treatment may involve electrical isolation of the pulmonary veins.Technologies designed to isolate the pulmonary veins or ablate specificpulmonary foci appear to be very promising and are the focus of much ofthe current research in catheter-based ablation techniques.

Certain cardiac surgical procedures involve administering ablativeenergy to the cardiac tissue in an attempt to create a transmural lesionon the tissue. However, with some current ablation approaches, includingRF, microwave, infrared laser, cryo-thermal, irreversibleelectroporation, and ultrasound ablation technologies, there may bedifficulties in making transmural lesions as desired. Thus, althoughcardiac ablation devices and methods are currently available and providereal benefits to patients in need thereof, many advances may still bemade to provide improved devices and methods for ablating epicardialtissue to treat AF and other arrhythmias. For example, there continuesto be a need for improved systems and methods that can effectivelydeliver ablative energy to patient tissue in a flexible manner,especially on the actively working heart. Embodiments of the presentinvention provide solutions that address the problems described above,and hence provide answers to at least some of these outstanding needs.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention provide systems and methods foradministering minimally invasive stand-alone atrial fibrillationtherapy, optionally involving the use of unipolar and bipolar ablationtechniques, and encompass treatments involving box lesions, connectinglesions, and conduction block. For example, embodiments encompasssystems and methods for performing cardiac and other surgicalprocedures. As described herein, an ablative lesion can be createdthermally by heating tissue with energy transmitted into tissue using,for example, microwave, infrared light, ultrasound waves, orradiofrequency (RF) energy. Alternatively, lesions can be formed byfreezing tissues below −40° C., or by killing tissue by non-thermalmeans, such as with radiation, toxic chemicals, or with irreversibleelectroporation.

One of the preferred ablative technologies is RF ablation. As disclosedherein, the terms “unipolar” and “monopolar” may be usedinterchangeably. Exemplary techniques involve the administration ofradiofrequency (RF) ablation energy, often in a temperature controlledmanner. Temperature control can be used to maintain tissue at desiredtemperatures when producing a lesion or lesion set. In some cases,internal probe cooling and suction mechanisms also help to ensurereproducible transmural, or full-thickness, endocardial or epicardiallesions. Such systems and methods can be used for minimally invasive ortraditional procedures either stand-alone or concomitant with valve orcoronary artery bypass graft (CABG) surgery, for example with access viasurgical access approaches including sternotomy, thoracotomy, portaccess, subxyphoid, transdiaphragmatic, or these in any combination.

Embodiments also encompass surgical systems that provide a minimallyinvasive epicardial surgical catheter which uses one or more electrodesto create contiguous lesions on a patient tissue. Exemplary techniquesinvolve a bipolar linear ablation probe that can be applied with suctionto a patient tissue. Suction stabilizer or pod mechanisms can operate topull atrial tissue flush to the probe, so as to ensure a consistent andreproducible lesion set. System configurations can help to overcome orcounteract the heat sink effect, while preventing or inhibiting theformation of coagulum at the tissue surface. Systems can be advancedthrough ports or small incisions, in order to create a lesion set on thepatient tissue. Suction mechanisms can ensure the precise delivery ofablation energy with minimal or no gaps. Systems can incorporateelectrode shielding mechanisms which help provide for theuni-directional delivery of ablation energy, without unwanted collateraltissue damage. The ablation energy output of individual ablationelectrodes can be automatically adjusted so as to accommodate forvariable tissue thicknesses. System and method embodiments of thepresent invention allow a surgeon to create a long contiguous lesionusing standard surgical techniques or minimally invasive approaches,including without limitation unilateral port access protocols, bilateralport access protocols, right mini-thoracotomy protocols, bilateralmini-thoracotomy protocols, and sternotomy protocols. By using suctionto assist in applying an ablation probe or mechanism, contact betweenthe ablation probe or mechanism can be optimized, and tissue gaps andthe potential for inadvertent heating or surrounding tissues can beeliminated. Power can be temperature regulated to use only the amount ofenergy desired to effectively create the lesion while maintaining tissueat safe temperatures. Exemplary system configurations can provide aneffective lesion by overcoming the heat sink and minimizing char. Forexample, cooling features such as internal cooling mechanisms canprevent or inhibit char and coagulum which act as an impedance barrierat the tissue surface and prevent or inhibit the delivery of ablationenergy to deep tissue structures. In some embodiments, saline or othercooling fluid can be circulated through an ablation probe or mechanismto prevent or inhibit such char and coagulum formation. The control ofheat removal and conduction is helpful in maintaining tissue temperatureat a desired level, for example above 50° Celsius, thus promoting afull-thickness lesion. In some instances, embodiments may includesystems having electrodes which are cooled by any of a variety ofcooling means. For example, a probe assembly may include internalcooling means disposed near or adjacent to one or more electrodes forcooling such electrodes.

Embodiments of the present invention further encompass bimodal systemsand methods, wherein an energy delivery device can be designated orselected to perform in either a monopolar mode or a bipolar mode. Forexample, either a monopolar or a bipolar mode can be selected by theoperator. In some instances, the operator may designate or select themonopolar mode or bipolar mode using a switch in the device handle. Insome instances, the operator may designate or select the monopolar modeor bipolar mode using a switch of a generator or electrosurgical unit(or a switch device attached thereto). In some instances, selection ofeither a monopolar or a bipolar mode can be performed by an algorithm ofthe generator. Relatedly, embodiments encompass a computer-readablemedium that stores instructions executable by one or more processors toperform a method of designating or selecting a monopolar mode or abipolar mode for operation of an electrosurgical unit. In someinstances, systems and methods may encompass a monopolar mode thatinvolves a double monopolar approach, wherein dual side-by-sideelectrode sets can deliver energy to the tissue one at a time or bothtogether. Such embodiments may include, for example, a first monopolarelectrode set positioned alongside a second monopolar electrode set. Insome instances, systems or methods may involve an electrode set, forexample a single monopolar electrode set, disposed along or in alignmentwith a centerline of a flexible stabilizer mechanism. Such embodimentscan form or provide an electrode planar or curved surface for contactinga tissue.

In one aspect, embodiments of the present invention encompass systemsand methods for administering an ablation treatment to a patient tissue.Exemplary systems may include a flexible stabilizer mechanism having aninner recess, and an ablation mechanism coupled with the stabilizermechanism. The ablation mechanism may include an active electrodeassembly disposed along a first side of the inner recess of thestabilizer mechanism, and a return electrode assembly disposed along asecond side of the inner recess of the stabilizer mechanism. In somecases, the flexible stabilizer mechanism is configured to deliversuction to a portion of the patient tissue, so as to draw the portion ofthe patient tissue into the inner recess of the stabilizer mechanism,and between the active electrode assembly and the return electrodeassembly. In some cases, systems may also include a temperature sensorin thermal association with the active electrode. In some cases, systemsmay also include a temperature sensor in thermal association with thereturn electrode. In some cases, systems may also include a temperaturesensor disposed along a central portion of the stabilizer mechanisminner recess. Embodiments of the present invention further encompasssystems having a cinching mechanism configured to constrict the ablationmechanism about the patient tissue. In some instances, an activeelectrode assembly may include at least 6 active electrodes. In someinstances, a return electrode assembly may include more than one returnelectrode. In some instances, systems may further include a secondactive electrode assembly disposed along the first side of the innerrecess of the stabilizer mechanism. In some instances, systems mayfurther include a second return electrode assembly disposed along thesecond side of the inner recess of the stabilizer mechanism. Optionally,a stabilizer mechanism may include a cooling lumen. In some cases, astabilizer mechanism may include an irrigation lumen. In some cases, astabilizer mechanism may include a pocket that channels a vacuumdelivered by the stabilizer mechanism. In some instances, a surgicalsystem may include an ablation device connector for coupling with anelectrosurgical unit. An ablation device connector may include couplingsfor delivering a pacing protocol to the patient via the ablationmechanism. Some surgical systems may include a steerable member inoperative association with the stabilizer mechanism. According to someembodiments, surgical systems may include a first rail coupled with afirst external side of the stabilizer mechanism, and a second railcoupled with a second external side of the stabilizer mechanism. In somecases, surgical systems may include a clamping instrument that tracksalong at least one of the first and second rails. In some instances, anactive electrode assembly may include an active electrode having anactive surface and a return electrode assembly may include a returnelectrode having a return surface, such that the active surface andreturn are angularly offset when the stabilizer mechanism is in arelaxed configuration and substantially parallel when the stabilizermechanism is in a clamped configuration.

In another aspect, embodiments of the present invention encompassmethods for administering an ablation treatment to a patient tissue.Exemplary methods may include placing a treatment assembly near thetissue of the patient. Such treatment assemblies may include a flexiblestabilizer mechanism having an inner recess and an ablation mechanismcoupled with the stabilizer mechanism. An ablation mechanism may includean active electrode assembly disposed along a first side of the innerrecess of the stabilizer mechanism, and a return electrode assemblydisposed along a second side of the inner recess of the stabilizermechanism. Methods may also include delivering a vacuum through thestabilizer mechanism so as to draw a portion of the patient tissue intothe inner recess of the stabilizer mechanism, and between the activeelectrode assembly and the return electrode assembly. Further, methodsmay include administering a bipolar ablation to the tissue via theablation mechanism to create a lesion in the tissue. In some instances,methods may include cinching the flexible stabilizer mechanism againstthe patient tissue prior to administering the bipolar ablation.

In another aspect, embodiments of the present invention encompasssystems for administering a treatment to a patient tissue. An exemplarysystem may include a flexible stabilizer mechanism having an innerrecess, a sheath that translates longitudinally relative to thestabilizer mechanism, and an ablation mechanism coupled with thestabilizer mechanism. The ablation mechanism may include a firstelectrode assembly disposed along a first side of the inner recess ofthe stabilizer mechanism, and a second electrode assembly disposed alonga second side of the inner recess of the stabilizer mechanism. In someinstances, the system is configured to provide a tissue ablationtreatment to the patient when the sheath is in a first configurationthat exposes a first amount of electrode assembly surface area, and atissue pacing treatment to the patient when the sheath is in a secondconfiguration that exposes a second amount of electrode assembly areathat is less than the first amount of electrode assembly surface area.According to some embodiments, systems may include a multifunctionconnector that connects the first and second electrode assemblies withan electrosurgical unit.

In still another aspect, embodiments of the present invention encompasssurgical system for administering an ablation treatment to a patienttissue. Exemplary surgical systems may include a flexible stabilizermechanism having an inner recess, and a ribcage mechanism disposed atleast partially within the inner recess of the stabilizer mechanism. Theribcage mechanism can have an inner recess. Systems may further includean ablation mechanism coupled with the ribcage mechanism. An ablationmechanism may include an active electrode assembly disposed along afirst side of the inner recess of the ribcage mechanism, and a returnelectrode assembly disposed along a second side of the inner recess ofthe stabilizer. In some instances, the flexible stabilizer mechanism canbe configured to deliver suction to a portion of the patient tissue, soas to draw the portion of the patient tissue into the inner recess ofthe ribcage mechanism, and between the active electrode assembly and thereturn electrode assembly.

In yet another aspect, embodiments of the present invention encompassmethods for administering an ablation treatment to a patient tissue.Exemplary methods may include placing a treatment assembly near thetissue of the patient. A treatment assembly may include a flexiblestabilizer mechanism having an inner recess, a ribcage mechanismdisposed at least partially within the inner recess of the stabilizermechanism, the ribcage mechanism having an inner recess, and an ablationmechanism coupled with the ribcage mechanism, the ablation mechanismcomprising an active electrode assembly disposed along a first side ofthe inner recess of the ribcage mechanism and a return electrodeassembly disposed along a second side of the inner recess of thestabilizer. Methods may also include delivering a vacuum through thestabilizer mechanism so as to draw a portion of the patient tissue intothe inner recess of the ribcage mechanism, and between the activeelectrode assembly and the return electrode assembly. Further, methodsmay include administering a bipolar ablation to the tissue via theablation mechanism to create a lesion in the tissue.

In another aspect, embodiments of the present invention encompasssurgical systems for administering an ablation treatment to a patienttissue. Exemplary surgical systems may include a flexible stabilizermechanism having a pod assembly housing a ribcage mechanism that definesan inner recess, and an ablation mechanism coupled with the ribcagemechanism. The ablation mechanism may include an electrode assemblydisposed along a first side of the inner recess of the ribcagemechanism, and a return electrode assembly disposed along a second sideof the inner recess of the ribcage mechanism. In some instances, theflexible stabilizer mechanism can be configured to deliver suction to aportion of the patient tissue, so as to draw the portion of the patienttissue into the inner recess of the ribcage mechanism, and between theactive electrode assembly and the return electrode assembly.

In another aspect, embodiments of the present invention encompassmethods for administering an ablation treatment to a patient tissue.Exemplary methods may include placing a treatment assembly near thetissue of the patient. The treatment assembly may include a flexiblestabilizer mechanism having a pod assembly housing a ribcage mechanismthat defines an inner recess, and an ablation mechanism coupled with theribcage mechanism. The ablation mechanism may include an electrodeassembly disposed along a first side of the inner recess of the ribcagemechanism and a return electrode assembly disposed along a second sideof the inner recess of the ribcage mechanism. Methods may also includedelivering a vacuum through the stabilizer mechanism so as to draw aportion of the patient tissue into the inner recess of the ribcagemechanism, and between the active electrode assembly and the returnelectrode assembly. Further, methods may include administering a bipolarablation to the tissue via the ablation mechanism to create a lesion inthe tissue.

In still a further aspect, embodiments of the present inventionencompass surgical systems or treatment assemblies for administering anablation treatment to a patient tissue. Exemplary surgical systems ortreatment assemblies may include a flexible stabilizer mechanismdefining an inner recess, and a ribcage mechanism disposed within theinner recess of the stabilizer mechanism. The ribcage mechanism candefine an inner recess. Surgical systems or treatment assemblies mayalso include an electrode mechanism disposed within the inner recess ofthe ribcage mechanism. The electrode mechanism can define an innerrecess for receiving a portion of the tissue for administration of amonopolar ablation treatment. In some instances, the flexible stabilizermechanism is configured to deliver suction through the ribcagemechanism, so as to draw the portion of the patient tissue into theinner recess of the electrode mechanism.

In another aspect, embodiments of the present invention encompassmethods for administering an ablation treatment to a patient tissue.Exemplary methods may include placing a treatment assembly near thetissue of the patient. A treatment assembly may include a flexiblestabilizer mechanism defining an inner recess, a ribcage mechanismdisposed within the inner recess of the stabilizer mechanism anddefining an inner recess, and an electrode mechanism disposed within theinner recess of the ribcage mechanism and defining an inner recess.Methods may also include delivering a vacuum through the stabilizermechanism and through the ribcage mechanism so as to draw a portion ofthe patient tissue into the inner recess of the electrode mechanism.Further, methods may include administering a monopolar ablation to thetissue via the electrode mechanism to create a lesion in the tissue.

In yet another aspect, embodiments of the present invention encompasssurgical systems for administering an ablation treatment to a patienttissue. Exemplary systems may include a flexible stabilizer mechanismhaving a pod assembly housing a ribcage mechanism that defines an innerrecess. Systems may also include an electrode assembly disposed withinthe inner recess of the ribcage mechanism. An electrode assembly maydefine an inner recess configured to receive a portion of the patienttissue and configured to transmit a monopolar ablation treatment to thetissue portion. In some instances, a flexible stabilizer mechanism canbe configured to deliver suction to the portion of the patient tissue,so as to draw the portion of the patient tissue into the inner recess ofthe electrode mechanism.

In still yet another aspect, embodiments of the present inventionencompass methods for administering an ablation treatment to a patienttissue. Exemplary methods may include placing a treatment assembly nearthe tissue of the patient. The treatment assembly may include anelectrode mechanism having an inner recess, a ribcage mechanism havingan inner recess housing the electrode mechanism, and a flexiblestabilizer mechanism having an inner recess housing the ribcagemechanism. Methods may also include delivering a vacuum through thestabilizer mechanism, the ribcage mechanism, and the electrodemechanism, so as to draw a portion of the patient tissue into the innerrecess of the electrode mechanism. Further, methods may includeadministering a monopolar ablation to the tissue via the electrodemechanism to create a lesion in the tissue.

In another aspect, embodiments of the present invention encompasssystems for administering an ablation treatment to a patient tissue.Exemplary systems may include a stabilizer mechanism having an innerrecess, and an ablation mechanism disposed within the inner recess ofthe stabilizer mechanism. The ablation mechanism may include a firstelectrode side and a second electrode side opposing the first electrodeside, the ablation mechanism configured to receive a portion of thetissue between the first electrode side and the second electrode side.In some instances, the stabilizer mechanism includes a pod assemblycoupled with a ribcage mechanism. In some instances, the ablationmechanism includes a ribcage mechanism coupled with an electrodemechanism.

In still a further aspect, embodiments of the present inventionencompass methods for administering an ablation treatment to a patienttissue. Exemplary methods may include placing a treatment assembly nearthe tissue of the patient. The treatment assembly may include astabilizer mechanism having an inner recess, and an ablation mechanismdisposed within the inner recess of the stabilizer mechanism. Theablation mechanism can have a first electrode side and a secondelectrode side opposing the first electrode side. Methods may alsoinclude delivering a vacuum through the stabilizer mechanism so as todraw a portion of the patient tissue into the inner recess of thestabilizer mechanism, and between the first electrode side and a secondelectrode side. Further, methods may include administering an ablationprotocol to the tissue via the ablation mechanism to ablate the tissueportion.

In some instances, the stabilizer mechanism includes a pod assemblycoupled with a ribcage mechanism. In some instances, the ablationmechanism includes a ribcage mechanism coupled with an electrodemechanism. In some instances, the ablation protocol includesadministration of a bipolar ablation. In some instances, the ablationprotocol includes administration of a monopolar ablation. In someinstances, the ablation protocol includes administration of a bipolarablation and a monopolar ablation.

In one aspect, embodiments of the present invention encompass surgicalsystems for administering a lesion forming treatment to a patienttissue. Exemplary systems may include a flexible stabilizer mechanismdefining an inner recess, a ribcage mechanism disposed within the innerrecess of the stabilizer mechanism, the ribcage mechanism defining aninner recess, and a lesion forming mechanism disposed within the innerrecess defined by the ribcage mechanism. The inner recess of the ribcagemechanism can be configured to receive a portion of the tissue foradministration of a lesion forming treatment. In some cases, the lesionforming mechanism includes a bipolar radiofrequency energy ablationmechanism, a monopolar radiofrequency energy ablation mechanism, a highvoltage pulse mechanism, a microwave energy mechanism, an infrared lasermechanism, a cryo-thermal mechanism, an ultrasound ablation mechanism, achemical ablation mechanism, or a radiation mechanism. In some cases,the flexible stabilizer mechanism is configured to deliver suction to aportion of the patient tissue, so as to draw the portion of the patienttissue into the inner recess defined by the ribcage mechanism, and intoproximity with the lesion forming mechanism. In some cases, thestabilizer mechanism includes or defines a pocket that channels a vacuumdelivered by the stabilizer mechanism. In some cases, a system alsoincludes a temperature sensor disposed along a central portion of thestabilizer mechanism inner recess. Optionally, the system may alsoinclude a cinching mechanism configured to constrict the lesion formingmechanism about the patient tissue. In some cases, the stabilizermechanism includes a pod assembly coupled with a ribcage mechanism.

In another aspect, embodiments of the present invention encompassmethods for administering a lesion forming treatment to a patienttissue. Exemplary methods may include placing a treatment assembly nearthe tissue of the patient, where the treatment assembly includes aflexible stabilizer mechanism defining an inner recess, a ribcagemechanism disposed within the inner recess of the stabilizer mechanismand defining an inner recess, and a lesion forming mechanism disposedwithin the inner recess defined by the ribcage mechanism. Methods mayalso include delivering a vacuum through the stabilizer mechanism andthrough the ribcage mechanism so as to draw a portion of the patienttissue into the inner recess defined by the ribcage mechanism. Further,methods may include administering the lesion forming treatment to thetissue via the lesion forming mechanism to create a lesion in thetissue. In some cases, the lesion forming mechanism includes a bipolarradiofrequency energy ablation mechanism, a monopolar radiofrequencyenergy ablation mechanism, a high voltage pulse mechanism, a microwaveenergy mechanism, an infrared laser mechanism, a cryo-thermal mechanism,an ultrasound ablation mechanism, a chemical ablation mechanism, or aradiation mechanism. In some cases, the stabilizer mechanism includes ordefines a pocket that channels the vacuum delivered through thestabilizer mechanism.

In another aspect, embodiments of the present invention encompasssurgical systems for administering a lesion forming treatment to apatient tissue. Exemplary systems may include a suction mechanismdefining an inner recess, and a lesion forming mechanism disposed withinthe inner recess defined by the suction mechanism. The suction mechanismis reinforced to resist collapse when a vacuum is present within theinner recess. The inner recess is configured to receive a curvilinearportion of the tissue for administration of the lesion forming treatmentthereto. In some instances, the curvilinear portion of patient tissueincludes a section having a thickness T, and wherein the inner recessdefined by the suction mechanism is configured to receive the sectiontherein, such that the section extends into the inner recess at adistance of greater than 0.5T. In some instances, the suction mechanismincludes a pod assembly housing a ribcage mechanism, and the ribcagemechanism operates to reinforce the suction mechanism so that thesuction mechanism resists collapse when a vacuum is present within theinner recess. In some instances, the suction mechanism is configured todeliver suction to a portion of the patient tissue, so as to draw theportion of the patient tissue into an inner recess defined by theribcage mechanism, and into proximity with the lesion forming mechanism.In some instances, the lesion forming mechanism includes a bipolarradiofrequency energy ablation mechanism, a monopolar radiofrequencyenergy ablation mechanism, a high voltage pulse mechanism, a microwaveenergy mechanism, an infrared laser mechanism, a cryo-thermal mechanism,an ultrasound ablation mechanism, a chemical ablation mechanism, or aradiation mechanism. In some instances, the lesion forming mechanismincludes a ribcage mechanism, and the ribcage mechanism operates toreinforce the suction mechanism so that the suction mechanism resistscollapse when a vacuum is present within the inner recess. Optionally,the suction mechanism may include or define a pocket that channels avacuum delivered by the suction mechanism. In some cases, a system mayalso include a temperature sensor disposed along a central portion ofthe inner recess. In some cases, a suction mechanism may include ordefine a cooling lumen. In some cases, a suction mechanism may includeor define an irrigation lumen.

In a further aspect, embodiments of the present invention encompasssurgical systems for administering a lesion forming treatment to apatient tissue. Exemplary surgical systems may include a stabilizermechanism defining an inner recess, and a lesion forming mechanismdisposed within the inner recess of the stabilizer mechanism. In somecases, the stabilizer mechanism includes a pod assembly housing aribcage mechanism. In some cases, the ribcage mechanism defines an innerrecess configured to receive a portion of the patient tissue, and thelesion forming mechanism is disposed within the inner recess defined bythe ribcage mechanism. In some cases, the lesion forming mechanism isconfigured to transmit the lesion forming treatment to the portion ofthe patient tissue. In some cases, the flexible stabilizer mechanism isconfigured to deliver suction to a portion of the patient tissue, so asto draw the portion of the patient tissue into an inner recess definedby the ribcage mechanism, and into proximity with the lesion formingmechanism. In some cases, the lesion forming mechanism includes aribcage mechanism. In some cases, the lesion forming mechanism includesa bipolar radiofrequency energy ablation mechanism, a monopolarradiofrequency energy ablation mechanism, a high voltage pulsemechanism, a microwave energy mechanism, an infrared laser mechanism, acryo-thermal mechanism, an ultrasound ablation mechanism, a chemicalablation mechanism, or a radiation mechanism. In some cases, thestabilizer mechanism includes or defines a pocket that channels a vacuumdelivered by the stabilizer mechanism. In some cases, a surgical systemmay also include a temperature sensor disposed along a central portionof the ribcage mechanism inner recess. In some cases, a stabilizermechanism may include or define a cooling lumen. In some cases, astabilizer mechanism may include or define an irrigation lumen

The terms “invention,” “the invention,” “this invention” and “thepresent invention” used in this patent are intended to refer broadly toall of the subject matter of this patent and the patent claims below.Statements containing these terms should be understood not to limit thesubject matter described herein or to limit the meaning or scope of thepatent claims below. Embodiments of the invention covered by this patentare defined by the claims below, not this Summary. This Summary is ahigh-level overview of various aspects of the invention and introducessome of the concepts that are further described in the DetailedDescription section below. This Summary is not intended to identify keyor essential features of the claimed subject matter, nor is it intendedto be used in isolation to determine the scope of the claimed subjectmatter. The subject matter should be understood by reference toappropriate portions of the entire specification of this patent, any orall drawings and each claim.

The above described and many other features and attendant advantages ofembodiments of the present invention will become apparent and furtherunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present invention are described indetail below with reference to the following drawing figures.

FIGS. 1A to 1M show aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 2A to 2D show aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 3A to 3E show aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 4 shows aspects of an electrode mechanism according to embodimentsof the present invention.

FIGS. 5 and 5A show aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 6A to 6D show aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 7, 7A, and 7B show aspects of surgical systems and methodsaccording to embodiments of the present invention.

FIGS. 8 and 8A show aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 9 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 10 and 10A show aspects of surgical systems and methods accordingto embodiments of the present invention.

FIGS. 11, 11A, 11B-1, 11B-2, and 11B-3 show aspects of surgical systemsand methods according to embodiments of the present invention.

FIGS. 12, 12A, and 12B show aspects of surgical systems and methodsaccording to embodiments of the present invention.

FIGS. 13 and 13A show aspects of surgical systems and methods accordingto embodiments of the present invention.

FIG. 14 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 15, 15A, 15B, 15C-1, 15C-2, 15C-3, 15D-1, 15D-2, 15D-3, 15E-1,15E-2, and 15E-3 show aspects of surgical systems and methods accordingto embodiments of the present invention.

FIG. 16 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 17 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIGS. 18 and 18A show aspects of surgical systems and methods accordingto embodiments of the present invention.

FIG. 19 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 20 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 21 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 22 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 23 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 24 shows aspects of surgical systems and methods according toembodiments of the present invention.

FIG. 25 shows aspects of surgical systems and methods according toembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The subject matter of embodiments of the present invention is describedhere with specificity to meet statutory requirements, but thisdescription is not necessarily intended to limit the scope of theclaims. The claimed subject matter may be embodied in other ways, mayinclude different elements or steps, and may be used in conjunction withother existing or future technologies. This description should not beinterpreted as implying any particular order or arrangement among orbetween various steps or elements except when the order of individualsteps or arrangement of elements is explicitly described.

Embodiments of the present invention encompass systems and methods forthe ablation of patient tissue or the formation of one or more lesionstherein. As such, exemplary techniques may employ any of a variety oflesion forming means, including bipolar radiofrequency energy ablationmechanisms, monopolar radiofrequency energy ablation mechanisms, highvoltage pulse mechanisms, microwave energy mechanisms, infrared lasermechanisms, cryo-thermal mechanisms, ultrasound ablation mechanisms,chemical ablation mechanisms, and radiation mechanisms. Exemplarysurgical systems can be employed during a treatment or procedure throughany of a variety of surgical access modalities, including withoutlimitation sternotomy, thoracotomy, port access, subxiphoid, and thelike. According to some embodiments, a treatment method may includeablating and monitoring a cardiac tissue of a patient with a tissuetreatment system. Treatment methods may also include techniques forplacing a tissue treatment system at a desired location within apatient. For example, a treatment method may include positioning atissue treatment system at or near the pulmonary veins of a patient. Asurgeon or operator may use an obturator and introducer assembly toposit the tissue treatment system at or near a specific location oranatomical feature of the patient. A treatment assembly or system caninclude any of a variety of tissue ablation mechanisms. In some cases, atreatment assembly can include an ablation element that transmits ordelivers RF energy to patient tissue. Optionally, suitable ablationelements can transmit or deliver infrared laser energy, high intensityfocused ultrasound (HIFU) energy, microwave energy, cryoablation energy,high-voltage pulses to ablate tissue by electroporation, and the like.Embodiments encompass treatment assemblies having multiple ablationelements, such as RF electrodes. In some cases, an treatment assemblymay include a single ablation element, such as a single RF ablationelectrode. Typically, an RF electrode is activated in its entiretyduring an ablation procedure. Longer lesion lengths can be made bymoving the electrode and ablating so that the ablations from the twoablation applications overlap. The procedure can be repeated until thedesired lesion pattern is completed.

In some instances, systems provide a bipolar ablation device configuredeither as a short segment device or a long belt device. Such bipolarablation devices can operate to produce a true bipolar transmurallesion, such that current is transmitted from one tissue surface to anopposing tissue surface, across the entire thickness of the tissue.Surgical systems as disclosed herein are well suited for use inproducing linear lesions or encircling lesions that circumscribe tissuestructures, such as one or more pulmonary veins. Ablation mechanisms canbe configured so that some elements, for example a first electrodeassembly, can operate to deliver RF energy and other elements, such as asecond electrode assembly, can operate to provide a return path for theRF energy. The first and second electrode assemblies can be directlyopposed to one another at opposite sides of a suction pod. For example,active and return electrode assemblies can be mounted on opposing sidesof an inner recess or concave surface of a suction pod. Patient tissue,such as a portion of the atrial wall, can be drawn into the vacuum podand sandwiched between the active and return electrodes. The suction podcauses the tissue to fold at least partially; reducing the effect ofheat sink on target tissue or to fold fully to cause completeendocardial tissue apposition. In this way, any of the monopolar orbipolar ablation protocols can be applied to the patient tissue.

Any of a variety of electrode configuration design and arrays can beused for ablating tissue with RF thermal ablation or for deliveringhigh-voltage pulses to the tissue to induce irreversibleelectroporation. For example, surgical systems may include planarelectrodes, cylindrical helical electrodes, linear wire, cable, or striptype electrodes, flat electrodes, and the like. Exemplary techniques fordelivering high-voltage pulse treatments to patient tissue are describedin U.S. patent application Ser. No. 13/149,687 filed May 31, 2011, thecontent of which is incorporated herein by reference. Systems caninclude any desired number of active and return electrodes. For example,systems may include 6 to 7 active electrodes and 1 to 2 returnelectrodes. Exemplary systems can be configured to delivery varioustypes of regulated energy, for example, RF energy which is controlled bymaintaining a set tissue temperature. Temperature sensors can be placedat multiple locations along the length and cross-section of the device,for example in close contact with one or more active ablatingelectrodes. Temperature sensors can also be placed along the center lineor central portion of the roof of the suction stabilizer to provide anindication of temperature at the tissue center away from ablation. Insome embodiments, a treatment system may include a cinching mechanism toallow the circumference of the suction stabilizer to be adjustable tothe tissue structure to be treated. A cinching mechanism may befacilitated by fixing a distal section of the suction stabilizer andretracting a proximal section of the suction stabilizer, or by aseparate mechanism that cinches both distal and proximal sections.

A linear array can also be achieved with the same or a different deviceconfigured in various lengths. By withdrawing the probe into a housingso that only the distal portion of the electrode is exposed, the samedevice may be used to achieve bipolar pacing with a suction applicatorto ensure tissue contact. Alternatively, distal leads can be wired orelectrically coupled with the distal end of the device and terminate indifferent pins distinct from the RF wiring of the distal electrodes. Apacing function can be performed by an ablation generator.Alternatively, an adaptor connector can be configured as identical to afemale connection of an ablation generator for insertion of the probecable with positive and negative male pins compatible with an externalpacemaker for subsequent suction applied pacing following an ablationprocedure. Belt devices may include visualization and delivery systems,including without limitation, scopes with protective lenses andintroducers with stylets, sheaths, or magnets, or combinations thereof.Belt devices can also include a marking system for identifying to theuser which electrodes are or are not in contact with tissue forablation.

Turning now to the drawings, FIG. 1A illustrates aspects of a tissuesurgical system 100 a according to embodiments of the present invention.As shown here, surgical system 100 a includes a handle mechanism 110 a,an ablation assembly or ablation probe mechanism 120 a, a power couplingassembly 130 a that connects with a power source such as anelectrosurgical unit (ESU), and a suction coupling assembly 140 a thatconnects with a vacuum source. Ablation assembly 120 a includes adistally positioned probe assembly 122 a and a proximally positionedprobe tubing assembly 124 a. FIG. 1B shows additional aspects ofsurgical system 100 b according to embodiments of the present invention.As depicted here, handle mechanism 110 b may include or be inoperational association with a probe tubing assembly 122 b, a powercoupling assembly 130 b having a cable 132 b that provides connectivitywith an ESU, and a suction coupling assembly 140 b having a suctiontubing 142 b. Probe tubing assembly 122 b may include a strain-relievedswivel 123 b that allows a grip assembly 112 b of the handle to remainflat without influencing axial rotation of the tubing 124 b, and abraided tube construction to flexibly transmit torque, probe power,temperature sensing, and suction, between various components of thesurgical system.

The handle also contains a switching mechanism 113 b for the user toselect between monopolar and bipolar modes. As shown here, the switchingmechanism 113 b includes a monopolar button 114 b and a bipolar button115 b. The buttons which actuate the switching mechanism have numerousfeatures to enhance user feedback to help the user to differentiate andrecognize quickly which mode the device is in, such as lighted buttons(e.g. 114 b, 115 b) that turn on when pushed, indicating that current isavailable to the circuit for the chosen mode. The handle is also shapedto minimize tubing snagging in the sterile field and is shaped toprevent accidental mode switching. For example, buttons 114 b, 115 b maybe recessed within the body of the handle mechanism.

FIG. 1C illustrates further features of an ablation assembly 120 caccording to embodiments of the present invention. As shown here,ablation assembly 120 c includes a suction stabilizer or pod mechanism123 c, one or more grab tabs 124 c, a magnet assembly 125 c located at adistal position on the ablation assembly, and a flexible proximal end126 c that provides a U-joint connection with an elongate member ortubing of the ablation assembly. Stabilizer mechanism 123 c defines asuction zone 127 c, which may contain or house electrodes or energytransmission members. In use, an operator may use an introducer or otherattachment means for coupling with magnet assembly 125 c, so as to allowthe operator to maneuver the ablation assembly as desired. For example,the operator may employ attachment, grasping, positioning, or introducersystems and navigation techniques such as those described in U.S. Ser.No. 12/124,743 filed May 21, 2008, U.S. Ser. No. 12/124,766 filed May21, 2008, U.S. Ser. No. 12/339,331 filed Dec. 19, 2008, and U.S. Ser.No. 12/879,106 filed Sep. 10, 2010, the contents of each of which areincorporated herein by reference. In some instances, a graspinginstrument with a magnetic distal section can be used to magneticallycouple with the ablation or probe assembly 120 c. The graspinginstrument can then be used to introduce, retrieve, or otherwisemanipulate, maneuver, or position the ablation probe assembly 120 c asdesired. A grasping means 124 c on the ablation probe assembly mayinclude flat, round, and/or toothed zones, and can also include multiplegrab tabs or fins for grasping with forceps or a similar instrument.Such features of a grasping means 124 c may allow freedom of graspingangles while maintaining control over bending and torsion of theablation probe assembly 120 c. In some instances, a distal section 121 cof the ablation probe assembly 120 c may include any of a variety ofshapes, in addition to or in place of grab tabs 124 c and/or magnetassembly 125 c, that can be grasped or coupled with an introducerassembly or other positioning device for maneuvering the ablationassembly. For example, distal section 121 c may present ball shapedfeatures, optionally with a neck, tabs with orientation features,keyhole slots, flat with grip ribs, and the like.

FIG. 1D depicts exemplary features of an ablation assembly 120 daccording to embodiments of the present invention. As shown here in anexemplary embodiment, ablation assembly 120 d includes a magnet assembly125 d, a ribcage mechanism 130 d having a flexible spine and ribconfiguration with electrode surfaces 135 d, and a proximal U-jointconnection 140 d. In some embodiments, an ablation assembly may includea suction stabilizer and a ribcage as separate element. In someembodiments, an ablation assembly may include a suction stabilizer and aribcage as a unified structure. Such a unified structure may be rigid orflexible. Further, such a separated or unified structure may bemechanically actuated in any of a variety of active or passive ways. Forexample, an ablation assembly, optionally in combination with a podassembly, can be actuated by an external mechanism such as a clamp, byan internal mechanism contained within the probe assembly, or by eitherpositive or negative pressure, such that moving parts of the ablationassembly or probe assembly are actuated. For example a tube or pluralityof tubes may deliver either suction or pressure, in gas or liquid form,to the ablation assembly or probe assembly, such that the pressuredifferential across the structural chambers, recesses, partitions, oractuation mechanism causes movement or applies a force. In this way, theablation assembly or probe assembly can squeeze tissue, open up spacefor tissue to enter, move electrodes into functional position, move theribcage and/or suction pod into a shape, in cross section or into acurvature or shape down the length of the assembly, in order to accessthe tissue site or create a lesion. Still further, such as unifiedstructure may include multiple rigid segments jointed together. In somecases, embodiments may involve a separate suction stabilizer andribcage, and the ribcage may also be rigid or flexible. Relatedly, sucha ribcage may be actuated in any of a variety of active or passive waysas described elsewhere herein. Still further, such a ribcage may beconstructed of rigid segments jointed together. In use, the ribcagemechanism 130 d can operate to prevent or inhibit the collapse of asuction pod mechanism (not shown) when a vacuum is applied therein. Theribcage mechanism 130 d can also provide a degree of flexibility forelectrodes attached therewith, to enhance or facilitate contact betweenthe electrodes and the patient tissue. By presenting a series of ribswith intervening spaces, the ribcage mechanism can also function as ascreen, thus allowing suction supplied from a vacuum source to passthrough the intervening spaces and to reach the patient tissue.

Surgical systems and methods for administering an ablation or lesionforming treatment to a patient tissue as described herein often involvea flexible stabilizer mechanism, a ribcage mechanism or reinforcementmember, and an ablation or lesion forming mechanism. In some cases, theablation assembly or lesion forming mechanism may include a bipolarradiofrequency energy ablation mechanism, a monopolar radiofrequencyenergy ablation mechanism, a high voltage pulse mechanism, a microwaveenergy mechanism, an infrared laser mechanism, a cryo-thermal mechanism,an ultrasound ablation mechanism, a chemical ablation mechanism, aradiation mechanism, or the like. As discussed elsewhere herein, lesionforming systems may include one or more electrodes. FIG. 1E shows anelectrode mechanism 110 e of an ablation assembly according toembodiments of the present invention. In some embodiments, an ablativeelement may present a cylindrical cross-section and be in the form of amicrowave antenna, a light diffusing optical fiber, or an ablationelectrode. In some embodiments, an ablation electrode may be flat andstraight or flat and two dimensionally curved to conform to the tissueor to cause the tissue to take a particular shape within the suctionrecess or cavity that enhances transmural lesion creation. As shownhere, an electrode mechanism may include distal barbs or couplingmechanisms 112 e and proximal tabs 114 e for coupling with a ribcagemechanism or other ablation assembly components as shown in FIG. 111. Asshown in FIG. 1E, electrode mechanism 110 e includes certain featuresthat confer flexibility to the electrode, and allow the electrode tomaintain apposition to ribs of a ribcage mechanism during theadministration of a treatment procedure. For example, the electrodeincludes a set of individual plates 120 e connected by interveningjunctions 130 e. Plates 120 e may be curved or contoured, for example asshown here presenting a concave surface, which can enhance contact orengagement with patient tissue during use. Junctions 130 e may beconstructed of thin or flexible wires or connector portions (e.g. havinga small diameter or cross-section), which facilitate the flexibility ofthe electrode mechanism 110 e in any three dimensional direction (e.g.along any x, y, z coordinate), and also facilitate twisting or torsionalflexibility of the electrode mechanism about a longitudinal axis. Asshown here, a first or upper portion 121 e of a plate 120 e may benarrower than a second or lower portion 122 e of plate 120 e, so thatwhen the electrode is bent in-plane in a curve as indicated by arrow A,an enhanced range of motion is achieved, until edges 125 e, contact oneanother or other mechanical interference within the electrode preventsfurther bending. According to some embodiments, portions of a suctionpod mechanism, which may include or be constructed of a flexiblematerial such as silicone rubber, may extend into spaces 126 e (e.g.intercostal spacings or gaps) between individual plates or tines 120 e.With continued reference to FIG. 1E, plates 120 e can be shaped orcontoured so as to contact the tissue with a desired shape and surfacearea for delivering energy to the tissue or receiving energy from thetissue. Junctions 130 e can connect plates 120 e together as a group orstring, mechanically and/or electrically, so as to provide onecontinuous electrode. Junctions 130 e can be shaped with a smallcross-section, curvature, and relatively long length in order to allowflexibility between adjacent plates 120 e. The electrode mechanism 110 eshown here is well suited for use in a bipolar ablation approach tothermally heat tissue with RF ablation or to apply high-voltage pulsesto ablate tissue with an irreversible electroporation technique, whereina probe assembly may include two or more of such electrode mechanisms.For example, a probe assembly may include one electrode mechanism on oneside of a ribcage mechanism, and another electrode mechanism on anopposing side of the ribcage mechanism, as discussed elsewhere herein.In some cases, a probe assembly may include multiple mechanisms along aside of a ribcage mechanism. For example, an ablation assembly asdepicted in FIG. 13 may include a set of two active electrode mechanismsalong one side of a ribcage mechanism. Relatedly, an ablation assemblyas depicted in FIG. 14 may include a set of seven active electrodemechanisms along one side of a ribcage mechanism.

FIG. 1F shows aspects of an ablation assembly 120 f having a suction podmechanism 123 f (depicted transparently, here), a ribcage mechanism 130f disposed in the suction pod mechanism 123 f, and a U-joint assembly140 f. In use, a suction recess or cavity 124 f defined by the suctionpod mechanism 123 f can operate to allow suction or negative pressure todraw tissue into the recess, and against or toward one or moreelectrodes of the ablation mechanism. As shown in FIG. 1G, an ablationassembly may have a suction pod mechanism defining suction zones invarious sizes. For example, ablation assembly configuration 120 gpresents a longer suction pod assembly 121 g, and ablation assemblyconfiguration 122 g presents a shorter suction pod assembly 123 g. Asshown here, ablation assembly 120 g includes a long probe assembly 124 gand a probe tubing assembly 125 g. Similarly, ablation assembly 122 gincludes a short probe assembly 126 g and a probe tubing assembly 127 g.

FIG. 1H depicts exemplary features of an ablation assembly 120 haccording to embodiments of the present invention. As shown here,ablation assembly 120 h includes a magnet assembly 125 h, a ribcagemechanism 130 h having a flexible spine and rib configuration, anelectrode mechanism 135 h coupled with the ribcage mechanism 130 h, anda U-joint connection 140 h. As shown here, a probe assembly may includethe ribcage and electrode assemblies, and a probe tubing assembly mayinclude elongate element 150 h which is coupled to the ribcage mechanismby a coupling mechanism 160 h. Elongate element 150 h and couplingmechanism 160 h can facilitate the transmission of a vacuum to theribcage mechanism 130 h, for example when elongate element 150 h andcoupling mechanism 160 h are disposed within a tubing (not shown) thatis in fluid communication with a suction pod (not shown) disposed aboutthe ribcage mechanism. The U-joint allows flexibility in all axes ofbending at the probe tube connection to the probe (as indicated byarrows A and B), allowing the positioning of the probe into tightanatomical corners and pockets, maintaining suction and electricalconnections from probe to handle, all the while allowing transmission oftorque to control the axial rotation of the probe from the externalaspect of the probe tubing. The system also includes a suction pod orsuction mechanism, such as those shown in FIGS. 1C, 1F, or 1G, whichcovers or houses the ribcage mechanism. In use, the sidewalls of theribcage mechanism 130 h are flexible, and can conform with a variety oftissue thicknesses.

According to some embodiments, the ribs or opposing walls of the ribcagemechanism are semi-rigid, so as to provide some degree of flex inresponse to tissue and some degree of rigidity in response to suction.For example, the semi-rigid side walls or ribs can flex so as tofacilitate the ingress of thicker tissue by spreading wider as thetissue moves between the side walls or opposing ribs and into thechamber. Relatedly, the semi-rigid side walls or ribs can resistexcessive flex so as to avoid collapse either outwardly or inwardly whensuction is administered through the suction pod and to the patienttissue.

In some instances, the suction pod, ribcage, and electrodes movetogether in unison, with the suction pod in contact with ribcage, andthe ribcage in contact with electrodes. Various types of movement orflexing may affect interactions between these ablation assemblycomponents. Similarly, use of the ablation assembly with tissues ofvarying thickness may also affect interactions between these ablationassembly components.

According to some embodiments, the entire probe (e.g. suction pod,ribcage, and electrodes) can flex up and down, flex side to side, andtwist in either direction (i.e. levorotation and dextrorotation), eitheralone or in any combination thereof. Such flexibility can be conferredat least in part by a ribcage mechanism having a serpentine spineconstruction with spacings between rib that change to accommodate suchmovement, by a suction pod mechanism constructed of a material thatstretches and compresses, and by one or more electrodes having flexiblefeatures which can maintain apposition to ribs of the ribcage mechanism.

Relatedly, according to some embodiments, each individual rib of aribcage mechanism can flex, such that ribs on one side (e.g right side)of the ribcage can flex either toward or away from ribs on an opposingside (e.g. left side) of the ribcage. In some cases, the ribs arerelatively inflexible but not rigid. For example, the ribs can besufficiently inflexible so that they can help to hold the suction pod orchamber in an open orientation (see, e.g., cross-section view of FIG.15). Also, the ribs can be sufficiently non-rigid, so that they canadjust to variations in tissue thickness (see, e.g., cross-section viewof FIG. 15B).

In some instances, very thin tissue to medium thickness tissue getsdrawn into suction chamber without affecting rib flex significantly. Insome instances, thick tissue may cause ribs to spread away from eachother in cross section several degrees. By providing a ribcage with ribsproviding passive stationary sidewalls with sufficient flexibility,tissues of varying thickness are allowed ingress into the chamber orbetween the opposing electrodes, thus enhancing electrode-tissue contactand tissue ablation.

In some instances, surgical systems may include ribcage mechanisms,suction pod mechanisms, or both, having active side walls, wheremovement of the ribcage and/or suction pod side walls can be drive bymechanisms other than suction. For example, clamping mechanisms may beused to actuate the side walls, thereby releasing or applying clampingpressure to tissue disposed between the opposing electrodes or ribs.

Exemplary surgical systems or belt devices may include or be used inconjunction with visualization and delivery systems including scopeswith protective lenses and introducers with stylets, sheaths, and ormagnets. Surgical systems or belt devices can also include a markingsystem for identifying to the user which electrodes are or are not incontact with tissue for ablation.

Tissue surgical systems disclosed herein are well suited for use insurgical procedures that involve ablating any of a variety of patienttissues, including without limitation the cardiac tissue of a humanheart. Exemplary tissue treatment systems may include an ablationassembly or an ablation probe mechanism, and a suction stabilizer or podmechanism. These components can be maneuvered or positioned within apatient as desired, optionally with the use of an introducer mechanism.A suction stabilizer or pod mechanism can operate to engage tissue undernegative pressure such that contact or proximity between the ablationprobe or electrode and the tissue to be coagulated is maintained asdesired throughout a procedure. An ablation probe mechanism can beconfigured to conform to the specific anatomy of the target tissue area.In some cases, a distal section of the probe mechanism can include oneor more ablation or coagulating electrodes. As disclosed herein, anablation probe mechanism or ablation assembly may provide a dualalignment electrode configuration, having a first electrode assembly anda second electrode assembly, arranged in a parallel manner. The firstand second electrode assemblies can be configured for the administrationof RF energy or high-voltage pulses to the patient tissue. For example,a first electrode assembly can operate to deliver the RF energy or highvoltage pulses, and a second electrode assembly can operate to provide areturn path. Surgical systems can be configured such that electrodeassemblies are directly opposed to one another at opposite sides of asuction pod. As disclosed herein, the electrode assemblies can bepositioned along a recessed trough or channel of the stabilizermechanism. Hence, surgical systems can provide a bipolar linear probe.By mounting active and return electrodes on opposite walls of a suctionpod, tissue can be drawn into the vacuum pod and sandwiched orpositioned between the active and return electrodes for the applicationof bipolar ablation. The surgical system can also include one or moreholders that can hold components of the ablation probe mechanism ortreatment assembly within or relative to the suction stabilizermechanism or tissue contacting assembly. Typically, during a surgicalprocedure the ablation probe mechanism is coupled with an energy source,and the suction stabilizer mechanism is coupled with a vacuum source. Inuse, tissue is drawn into the stabilizer channel or cavity, so as to bepositioned between the electrodes. When a treatment or medical procedureis completed, the ablation probe mechanism may be decoupled from theenergy source.

Placement of the electrode assemblies within an inner recess or chamberof the stabilizer pod allows the system to provide enhanced directheating of the tissue with RF or provides a more uniform field patternto enable irreversible electroporation with lower applied voltages thanwould be possible with other electrode configurations. Moreover, in usesuch configurations can significantly reduce the amount of convectivecooling in tissue which might otherwise occur. This reduction ofconvective cooling is especially important when the system is engagedwith the epicardial surface of the working heart, in which case a dimpleis created in the endocardium and convective cooling is reduced oreliminated at that location.

This reduction of endocardial convective cooling also occurs when thesystem is engaged with the epicardial surface of the working heart usingthermal ablative elements other than RF within an inner recess orchamber of the stabilizer pod. The resultant structure of the chamber ofthe stabilizing pod with strategic placement of the ablation elementstherein enable transmural lesion creation with ablative energy sourcesthat do not ordinarily create lesions through the full thickness of theatrial wall. In one alternative embodiment, piezoelectric ultrasonictransducers capable of heating tissue to ablation temperatures can beplaced along the opposing walls of the chamber at locations similar tothe locations of electrodes used for bipolar RF ablation. For example,FIG. 15C-1 depicts a cross-section view of aspects of a surgical system1500 c according to embodiments of the present invention. Surgicalsystem 1500 c includes an ablation assembly or lesion forming mechanism1510 c at least partially disposed within an inner recess 1530 c definedby a suction or stabilizer mechanism 1520 c. As depicted here, lesionforming mechanism or ablation assembly 1510 c includes two opposinglesion forming elements. FIG. 15C-2 illustrates a top plan view ofadditional aspects of the surgical system. The lesion forming mechanismor ablation assembly 1510 c includes a first lesion forming element 1515c and a second lesion forming element 1525 c. The lesion formingelements may include individual transducers T with spaces Stherebetween. In some cases, each transducer T is shaped to emit anon-converging ultrasonic beam and has a length within a range fromabout 0.5 cm to about 2 cm, and spaces S between transducers T have alength within a range from about 1 to about 3 cm. In some case, thetransducers on the facing walls are equal in size and are located tocenter on the spaces between the transducers on the facing walls. Forthis ablative technology, the suction stabilizer pod structures not onlyreduces endocardial cooling, but also ensures that the tissue is drawninto intimate air-free contact with the ultrasound transducer surface toenable effective transfer of ultrasound energy into the tissue.Ultrasound energy provided by the transducer can be unfocused, orslightly focused. Often, the transducer will generate a uniformultrasound field. The intensity of the delivered ultrasound may diminishas the energy radiates throughout the tissue, for example as a functionof the distance from the transducer. The amount or degree to which theintensity diminishes may depend on the frequency of the ultrasoundapplied. During operation of the system, the ultrasound energy may beabsorbed by the patient's tissue due to vibrational absorption. Higherfrequency ultrasound may be absorbed more strongly than lower frequencyultrasound. The transducer configuration (e.g. crystal type) may beselected based on a dimension (e.g. width, height, cross-section area)of the recess or chamber 1530 c. For example, for recesses having asmaller width, it may be desirable to use a transducer that provides ahigher frequency (e.g. such that energy is absorbed in a smaller area).Often, it will be desirable to provide uniform heating at a distancefrom the transducer. Such heating can be a result of the patient tissueabsorbing the ultrasound energy. Hence, the transducer configuration andthe dimensions of the recess can be carefully selected, so as to be ableto provide ultrasound energy to a well-defined amount of tissue in acontrolled manner. As depicted elsewhere herein, suction can be used todraw a portion of the tissue into the recess, thus eliminating orreducing the amount of air in the ultrasound administration region, thusfurther enhancing the effectiveness of the ultrasound treatment. In somecases, the system can provide an even temperature gradient within therecess. In some cases, for example where relatively higher frequenciesare used, there may be a localized temperature gradient within thetissue, as tissue closer in proximity to the transducer becomes hottermore quickly. In some instances, a transducer configuration or frequencyis selected so that a majority of the ultrasound energy is absorbed overthe first half of the distance between opposing sides of the recess. Asdepicted in FIG. 15C-3, a conductive heating pattern can radiate fromone side to another (as indicated by arrow A) and also laterally (asindicated by arrows B). As such, the heating pattern can radiateoutwardly from a transducer, within the patient tissue. In someinstances, the system can be configured so that the energy intensity isabout 50% at a distance of about halfway between opposing sides of therecess. Techniques for determining ultrasound parameters are discussedat, for example, Ergun, “Analytical and numerical calculations ofoptimum design frequency for focused ultrasound therapy and acousticradiation force” Ultrasonics, 51(7): 786-94 (October 2011), the contentof which is incorporated herein by reference.

For cryoablation applications, the structure of chamber or inner recessof the stabilizing pod can be used effectively to greatly reduce oreliminate endocardial convective warming. Such convective warmingordinarily prevents transmural lesion formation with epicardialapplication of a cryoablation probe to the epicardium of the workingheart. In one embodiment of the invention, tissue is cooled along theopposing walls of the chamber or inner recess using cooling memberscontained within the wall of the suction stabilizing pod. For example,FIG. 15D-1 illustrates a cross-section view of a treatment system 1500 dhaving a suction stabilizing pod 1510 d that defines an inner recess1520 d, and two opposing lesion forming mechanisms 1530 d, 1540 d. Insome cases, lesion forming mechanisms may include a balloon ( 1532 d,1542 d) disposed about a hypotube (1534 d, 1544 d), and a thermalconductive element (1536 d, 1546 d) adjacent the balloon. FIG. 15D-2provides a corresponding side view of aspects of a lesion formingmechanism having a balloon 1542 d and hypotube 1544 d. In one exemplaryembodiment, a lesion forming mechanism or cooling assembly can includean elongate balloon having a diameter within a range from about 2 mm toabout 3 mm, that is mounted over a hypotube having an internal diameterwithin a range from about 0.2 mm to about 0.3 mm. In some cases, withinthe balloon, the hypotube may contain holes H (for example having adiameter within a range from about 0.01 mm to about to 0.03 mm) that arespaced apart (for example with a spacing of about 1 cm between adjacentholes) through which coolent can be sprayed to cool and inflate theballoon during the active freezing cycle. Liquid N₂O is one preferredcoolent, but various other coolents could be used as well, such asDuPont ISCEON Refrigerents, Argon or Nitrogen. For croyablation systems,cooling results from the Joule-Thompson effect and if the coolent isdelivered as a liquid, from the latent heat of vaporization. For thepreferred coolent of liquid N₂O, it is believed that the latent heat ofvaporization contributes to the majority of the cooling with balloonstructure described. With returning reference to FIG. 15D-1, the coolingballoons 1532 d, 1542 d can be placed in direct physical contact withconductive elements or metallic structures 1536 d, 1546 d to facilitatethermal transfer between the tissue within the pod and the coolingballoon. These metallic structures can be similar to RF electrodesdescribed elsewhere herein, because the metallic structures can be veryflexible and can provide good thermal conduction along their length.During the administration of a lesion forming or ablative treatment,cold temperature from the balloon is transmitted to patient tissue whichis positioned within the recess 1520 d, for example via the conductiveelement or metallic structure. Generally, the pressure within thehypotube is such that the cryogenic material is maintained in a liquidstate until exiting the holes. For example, the hypotube may be at roomtemperature (e.g. 20 to 25° C.) or body temperature (e.g. 35 to 38° C.),and the cryogenic material is pressurized so that it is liquid at thistemperature. As shown in FIG. 15D-3, a pressurized liquid that isdelivered through hypotube 1544 d can exit holes H of the hypotube, andconvert to gas as it enters the space between the hypotube and theballoon walls 1542 d. Typically, there is a drop in pressure, as thematerial moves from an area of higher pressure (within the hypotube) toan area of lower pressure (between the hypotube and the balloon walls).Also, the cryogenic liquid typically expands upon passing through theholes H. In this way, the flow of cryogenic material from the inside ofthe hypotube to the outside of the hypotube generates a coolingmechanism in two ways. First, the cryogenic substance (e.g. N₂O) becomescooler due to the pressure drop (e.g. decompression). Second, thecryogenic substance become cooler due to evaporation, as it transitionsfrom a liquid to a gas. As depicted in FIG. 15D-2, holes H can be spacedalong the length of the hypotube. Accordingly, the cooling effect, whichis generated at the holes, is distributed along the length of thehypotube and balloon. In this way, it is possible to control where thecooling occurs. Typically, the hypotube is a small flexible and/orelastic pipe. In some instances, the hypotube may be constructed ofnitinol or another material having similar shape memory and elasticityproperties. In some instances, the hypotube can be constructed ofstainless steel. The hypotube can be configured so that it presentsappropriate flexing and bending properties. The dimensions of the holesor apertures are selected so that the desired amount of back-pressure ismaintained (thus keeping the material in a liquid state) within thehypotube as the cryogenic material exits the holes. The pressure withinthe balloon (e.g. between the hypotube and balloon wall) can be near orslightly above atmospheric pressure. Hence, the cryogenic material orcoolant enters the hypotube/balloon mechanism in a liquid state, andexits therefrom in a gaseous state. In some cases, the cryogenicmaterial or coolant enters the hypotube/balloon mechanism in a gaseousstate (high pressure) and exits therefrom in a gaseous state (lowpressure). As the cryogenic material exits the holes H, it operates toexpand the balloon from a relaxed configuration to an expandedconfiguration.

In some instances, as depicted in FIGS. 15E-1, 15E-2, and 15E-3, asurgical system 1500 e for administering a lesion forming treatment to apatient tissue may include a suction mechanism 1510 e defining an innerrecess 1520 e, and a lesion forming mechanism 1530 e disposed within theinner recess 1520 e. The suction mechanism 1510 e can be reinforced(e.g. with a ribcage mechanism) to resist collapse when a vacuum ispresent within the inner recess 1520 e. As illustrated here, the innerrecess 1520 e can be configured to receive a curvilinear portion CP towhich the lesion forming treatment is administered. The curvilinearportion of tissue may have a section 1550 e having a thickness T. Asshown here, the curvilinear portion CP of tissue includes three regionsor section along its length having tissue thickness values of T₁, T₂,and T₃, respectively. In some cases, the values of T₁, T₂, and T₃ areequivalent. In some cases, the values of T₁, T₂, and T₃ may differ fromone another. FIG. 15E-2, depicts a cross-section view of the patienttissue, before suction is applied. As shown here, only a small portion1550 e of the patient tissue extends into the recess 1520 e. Forexample, the tissue as depicted here extends into the recess by adistance D. In some instances, the tissue does not extend into therecess before suction is applied. This may represent a normal curved orundistorted configuration of the patient tissue, for example atrialtissue, before the tissue is drawn in suction recess. The amount towhich the tissue extends into the recess (e.g. distance D) can be due tothe normal curvature and may also depend on the thickness or flexibilityof the tissue. For example, a thin tissue may extend further into therecess than a thick tissue. FIG. 15E-3, depicts the tissue (e.g. thecurvilinear portion CP) after it has been drawn into the recess 1520 e,due to application of the suction. The amount of or degree to which thetissue extends into the recess may depend on various factors, such astissue thickness. For example, for a long lesion, for a portion of thelesion length, the entire wall thickness may be within the chamber, butalong other portions, where the tissue is thicker, only 50% of the wallthickness may be within the chamber. For a curvilinear length of 15 cm,for example, the wall thickness may vary by 3-fold or more along thelength of the anticipated lesion. The amount to which the tissue extendsinto the recess (e.g. distance D) can be due to the normal curvature andmay also depend on the thickness or flexibility of the tissue. Forexample, FIGS. 6B and 6C illustrate that a thin tissue may extendfurther into the recess than a thick tissue. In some cases, the innerrecess 1520 e can be configured to receive the section 1550 e therein,such that the section 1550 e extends into the inner recess at a distanceD that is greater than 0.5 T. As shown in FIG. 15E-3, the tissue becomedistorted, deviating from its normal cross section, as it is drawn intothe recess 1520 e. The recess depicted in this drawing is mostly filledwith tissue.

According to some embodiments, a surgical system can include two or moremetallic RF ablation electrode assemblies coupled with a siliconesuction stabilizer pod. For example, a first electrode assembly caninclude two active (−) electrodes, and a second electrode assembly caninclude one return (+) electrode. During the administration of asurgical treatment procedure, the system can be inserted through a portpositioned at the side of a patient, and between the patient's ribs. Thesystem can then be advanced along a posterior surface of the heart, forexample so that the exposed electrodes encircle one or more of thepatient's pulmonary veins. When the stabilizer pod is positioned asdesired, a vacuum or negative pressure can be applied via the stabilizerpod. Tissue is drawn into or toward the stabilizer inner recess, and thesuction operates to approximate the ablation electrodes with the tissue.Ablation energy can then be applied to the tissue via the electrodes sothat current flows from the active electrodes to the return electrodes,thereby establishing a current density within the intervening tissue soas to create a transmural lesion therein. In some instances, deliveryand return wires can pass through the stabilizer outer surface toconnect with the electrodes.

As described herein, ablation assemblies can include active electrodesand return electrodes. Often, return electrodes may also be referred toas indifferent or passive electrodes. Both active electrodes and returnelectrodes may be considered to provide electrical conductivity orconduction, and hence both can be considered to function electrically.Typically, power or energy (e.g. current pulses having an amplitude) isprovided by an active electrode.

Suction stabilizer or pod mechanisms may present any of a variety ofcross-section configurations. As shown in FIG. 1I, pod mechanism orassembly 120 i provides a backbone structure having a curved convexouter surface 121 i and a curved concave inner surface 122 i. FIG. 1Jillustrates a suction pod mechanism or assembly 120 j having a backbonestructure with a square or rectangular outer surface 121 j and a squareor rectangular inner surface 122 j. FIG. 1K illustrates a suction podmechanism or assembly 120 k having a backbone structure with atrapezoidal outer surface 121 k and a trapezoidal inner surface 122 k.FIG. 1K-A illustrates a suction pod mechanism or assembly 120 k-a havinga backbone structure with a hourglass outer surface 121 k-a and atrapezoidal inner surface 122 k-a. Exemplary suction pod mechanisms canpresent any of a variety of combinations of such outer and inner surfaceshapes. Pod mechanism inner and outer surface shapes can configured tomeet various criteria or objectives. For example, pod mechanism innerand outer surface shapes can be configured to fit within the confines ofa desired port or delivery system. In some instances, pod mechanisminner and outer surface shapes can be configured to decrease or minimizethe friction and catch points during axial advancement and retractionthrough the tissue planes and past structures along the delivery path.In some instances, pod mechanism inner and outer surface shapes can beconfigured to increase or maximize the range of tissue thicknesses thatcan be drawn into the suction recess. In some instances, pod mechanisminner and outer surface shapes can be configured to remain stable andcontrollable with the suction opening oriented toward target tissue. Insome instances, pod mechanism inner and outer surface shapes can beconfigured to maintain an inner suction recess shape while allowingflexibility under the application of suction. In some instances, podmechanism inner and outer surface shapes can be configured to allow adegree of expansion of the suction opening when engaging thick tissuesas a function of differential wall thickness, wall angles, materials,contact edge geometry, electrode mounting, and suction pressure. In someinstances, pod mechanism inner surface shapes or margin dimensions canbe configured to enhance tissue ingress within the probe assembly. Forexample, tissue slides past the suction pod margins or edges as it isdrawn into the pod, and margins or edges can be shaped and/or sized tofacilitate this ingress.

FIG. 1L shows a schematic for a surgical system 1001 according toembodiments of the present invention. Surgical system 1001 includes ahandle mechanism 1101 coupled or in operative association with anablation assembly or ablation probe mechanism 1201, a power sourceassembly 1401 such as an electrosurgical unit (ESU), and a vacuum sourceassembly 1301.

According to some embodiments, a power source assembly orelectrosurgical unit (ESU) may include or be in operative associationwith a computer system for controlling various aspects of a surgicalsystem. FIG. 1M is a simplified block diagram of an exemplary computersystem 100 m that broadly illustrates how individual system elements oraspects of a tissue treatment computer system may be implemented in aseparated or more integrated manner. For example, an ESU may include acomputer system that provides instructions to or interfaces with anablation mechanism. Computer system 100 m is shown comprised of hardwareelements that are electrically coupled via a bus subsystem 102 m,including one or more processors 104 m, one or more input devices 106 msuch as user interface input devices, one or more output devices 108 msuch as user interface output devices, and a network interface 110 m.

In some embodiments computer system 100 m also comprises softwareelements, shown as being currently located within working memory 112 mof memory 114 m, including an operating system 116 m and other code 118m, such as a program designed to implement method embodiments of thepresent invention. In some instances, code may be embodied oncomputer-readable media, such as register memory, processor cache, orRAM.

Likewise, in some embodiments computer system 100 m may also include astorage subsystem 120 m that can store the basic programming and dataconstructs that provide the functionality of the various embodiments ofthe present invention. For example, software modules implementing thefunctionality of the methods of the present invention, as describedherein, may be stored in storage subsystem 120 m. These software modulesare generally executed by the one or more processors 104 m. In adistributed environment, the software modules may be stored on aplurality of computer systems and executed by processors of theplurality of computer systems. Storage subsystem 120 m can includememory subsystem 122 m and file storage subsystem 128 m. Memorysubsystem 122 m may include a number of memories including a main randomaccess memory (RAM) 126 m for storage of instructions and data duringprogram execution and a read only memory (ROM) 124 m in which fixedinstructions are stored. File storage subsystem 128 m can providepersistent (non-volatile) storage for program and data files, and mayinclude tangible storage media which may optionally embody patient,device, treatment, evaluation, positioning, or other medical data. Filestorage subsystem 128 m may include a hard disk drive, a floppy diskdrive along with associated removable media, a Compact Digital Read OnlyMemory (CD-ROM) drive, an optical drive, DVD, CD-R, CD-RW, solid-stateremovable memory, other removable media cartridges or disks, and thelike. One or more of the drives may be located at remote locations onother connected computers at other sites coupled to computer system 100m. The modules implementing the functionality of embodiments of thepresent invention may be stored by file storage subsystem 128 m. In someembodiments, the software or code can provide protocols to allow thecomputer system 100 m to communicate with communication network 130 m.Often such communications can include dial-up or internet connectioncommunications, wireless communications, or any other desired orsuitable connectivity.

It is appreciated that system 100 m can be configured to carry outvarious method aspects of the present invention. For example, processorcomponent or module 104 m can be a microprocessor control moduleconfigured to receive data or signals from input device or module 106 m,and transmit data or signals to output device or module 108 m and/ornetwork interface device or module 110 m. Each of the devices or modulesof the present invention can include software modules on a computerreadable medium that is processed by a processor, hardware modules, orany combination thereof. Any of a variety of commonly used platforms,such as Windows, MacIntosh, and Unix, along with any of a variety ofcommonly used programming languages, such as C or C++, may be used toimplement embodiments of the present invention. In some cases, tissuetreatment systems include FDA validated operating systems orsoftware/hardware modules suitable for use in medical devices. Tissuetreatment systems can also include multiple operating systems. Forexample, a tissue treatment system can include a FDA validated operatingsystem for safety critical operations performed by the treatment system,such as data input, power control, diagnostic procedures, recording,decision making, and the like. A tissue treatment system can alsoinclude a non-validated operating system for less critical operations.

User interface input devices 106 m may include, for example, a touchpad,a keyboard, pointing devices such as a mouse, a trackball, a graphicstablet, a scanner, a joystick, a touchscreen incorporated into adisplay, audio input devices such as voice recognition systems,microphones, and other types of input devices. User input devices 106 mmay also download a computer executable code from a tangible storagemedia or from communication network 130 m, the code embodying any of themethods of the present invention. It will be appreciated that terminalsoftware may be updated from time to time and downloaded to the terminalas appropriate. In general, use of the term “input device” is intendedto include a variety of conventional and proprietary devices and ways toinput information into computer system 100 m.

User interface output devices 108 m may include, for example, a displaysubsystem, a printer, a fax machine, or non-visual displays such asaudio output devices. The display subsystem may be a cathode ray tube(CRT), a flat-panel device such as a liquid crystal display (LCD), aprojection device, or the like. The display subsystem may also provide anon-visual display such as via audio output devices. In general, use ofthe term “output device” is intended to include a variety ofconventional and proprietary devices and ways to output information fromcomputer system 100 m to a user. In some cases, a tissue treatmentsystem can include an integrated user interface device, where featuresof user interface input device 106 m are combined with features of userinterface output device 108 m.

Bus subsystem 102 m provides a mechanism for letting the variouscomponents and subsystems of computer system 100 m communicate with eachother as intended. The various subsystems and components of computersystem 100 m need not be at the same physical location but may bedistributed at various locations within a distributed network. Althoughbus subsystem 102 m is shown schematically as a single bus, alternateembodiments of the bus subsystem may utilize multiple busses.

Network interface 110 m can provide an interface to an outside network130 m and/or other devices. Outside communication network 130 m can beconfigured to effect communications as needed or desired with medicalpersonnel, institutions, or other entities. It thus can receive anelectronic packet from computer system 100 m and transmits anyinformation or signal as needed or desired back to computer system 100m. In addition to providing such infrastructure communications linksinternal to the system, the communications network system 130 m may alsoprovide a connection to other networks such as the internet and maycomprise a wired, wireless, modem, and/or other type of interfacingconnection. As noted above, in some embodiments, a computer system canbe in integrated into a tissue treatment system, and in someembodiments, a computer system can be separate from, but in connectivitywith, a tissue treatment system. Hence, a computer system 100 m caninclude a system interface 140 m that provides an interface to a tissuetreatment system 150 m. In some cases, a tissue treatment system 150 mmay include an ablation assembly, optionally in combination with avacuum assembly or a handle mechanism, as disclosed elsewhere herein.

It will be apparent to those skilled in the art that substantialvariations may be used in accordance with any specific requirements. Forexample, customized hardware might also be used and/or particularelements might be implemented in hardware, software (including portablesoftware, such as applets), or both. Further, connection to othercomputing devices such as network input/output devices may be employed.Computer terminal system 100 m itself can be of varying types includinga computer terminal, a personal computer, a portable computer, aworkstation, a network computer, or any other data processing system.Due to the ever-changing nature of computers and networks, thedescription of computer system 100 m depicted in FIG. 1M is intendedonly as a specific example for purposes of illustrating one or moreembodiments of the present invention. Many other configurations ofcomputer system 100 m are possible having more or less components thanthe computer system depicted in FIG. 1M. Relatedly, any of the hardwareand software components discussed above can be integrated with orconfigured to interface with other medical treatment or informationsystems used at other locations.

FIG. 2A provides a cross-section view of a surgical system 200 inoperational engagement with a patient tissue 200 a having a thickness T.Surgical system 200 includes an ablation probe mechanism having a firstelectrode assembly 212 and a second electrode assembly 214. The ablationprobe mechanism is coupled with a suction stabilizer mechanism 220. Asshown here, suction mechanism 220 includes an outer convex surface orshell 222 and an inner concave recess or cavity 224. First electrodeassembly 212 is located at a first position 224 a along inner cavity224, and second electrode assembly 214 is located at a second position224 b along inner cavity 224 opposite the first position 224 a. Firstelectrode assembly 212 and second electrode assembly 214 can present abipolar configuration. For example, first electrode assembly 212 canprovide an active electrode for delivering RF energy, and secondelectrode assembly 214 can provide a return electrode for returning RFenergy. As shown here, a section 230 b of patient tissue is drawn intothe inner recess of the suction stabilizer. During the administration ofa bipolar ablation treatment, current 240 passes through this section ofpatient tissue, from the active electrode 212 to the return electrode214. As the current sufficiently heats the tissue, for example bypassing from one tissue surface 250 to an opposing tissue surface 260,across the entire thickness T of the tissue, a transmural lesion iscreated.

FIG. 2B provides a cross-section view of a surgical system 200 inoperational engagement with a patient tissue 200 b having a thickness2T, which is twice the tissue thickness represented in FIG. 2A. Surgicalsystem 200 includes an ablation probe mechanism having a first electrodeassembly 212 and a second electrode assembly 214. The ablation probemechanism is coupled with a suction stabilizer mechanism 220. As shownhere, suction mechanism 220 includes an outer convex surface or shell222 and an inner concave recess or cavity 224. First electrode assembly212 is located at a first position 224 a along inner cavity 224, andsecond electrode assembly 214 is located at a second position 224 balong inner cavity 224 opposite the first position 224 a. Firstelectrode assembly 212 and second electrode assembly 214 can present abipolar configuration. For example, first electrode assembly 212 canprovide an active electrode for delivering RF energy, and secondelectrode assembly 214 can provide a return electrode for returning RFenergy. As shown here, a section 230 of patient tissue is drawn into theinner recess of the suction stabilizer. During the administration of abipolar ablation treatment, current 240 b passes through this section ofpatient tissue, from the active electrode 212 to the return electrode214. As shown here, the increased thickness 2T of the patient tissue canmake it difficult for system 200 to administer a fully transmurallesion.

Hence, it may be desirable to use a surgical system having a largersuction stabilizer when treating thicker tissue. A suction stabilizerhaving a larger recess can be helpful for accommodating a thickertissue, so that the tissue, which may be the atrial wall of a patient,is drawn sufficiently into the recess and between the electrodes. Forexample, FIG. 2C, shows a cross-section view of surgical system 200 c inoperational engagement with a patient tissue 200 b having a thickness2T. Surgical system 200 c includes an ablation probe mechanism having afirst electrode assembly 212 c and a second electrode assembly 214 c.The ablation probe mechanism is coupled with a suction stabilizermechanism 220 c. As shown here, suction mechanism 220 c includes anouter convex surface or shell 222 c and an inner concave recess orcavity 224 c. First electrode assembly 212 c is located at a firstposition 224 d along inner cavity 224 c, and second electrode assembly214 c is located at a second position 224 e along inner cavity 224 copposite the first position 224 d. First electrode assembly 212 c andsecond electrode assembly 214 c can present a bipolar configuration. Forexample, first electrode assembly 212 c can provide an active electrodefor delivering RF energy, and second electrode assembly 214 c canprovide a return electrode for returning RF energy. As shown here, asection 230 c of patient tissue is drawn into the inner recess of thesuction stabilizer. During the administration of a bipolar ablationtreatment, current 240 c passes through this section of patient tissue,from the active electrode 212 c to the return electrode 214 c. As thecurrent sufficiently heats the tissue, for example by passing from onetissue surface 250 c to an opposing tissue surface 260 c, across theentire thickness 2T of the tissue, a transmural lesion is created.

Exemplary systems described herein are well suited for use in ablatingatrial tissue, which typically has a thickness of about 4 mm. For atrialwall ablation, some configurations for the suction pod cavity or recesscan have a well depth of about 5 to 10 mm, and a well width at thesidewall opening of about 5 to 10 mm. Similarly, systems with suctionpods that are somewhat deeper and wider can be used for ablating theepicardium of the ventricle.

As indicated in FIG. 2C, tissue is sucked up into the “U” shaped suctionstabilizer, and current density 240 c spreads through or across thepatient tissue disposed between the electrodes. In turn, the tissuebecomes heated and a lesion forms. Upon heating and ablation, a changein tissue color (e.g. red changing to brown) can be observed from theopposing side of the tissue, at location 260 c. Upon removal of thesystem 200 c, the patient tissue resumes a flattened or straightenedconfiguration. As shown in the tissue cross-section view of FIG. 2D, theresulting ablation pattern 275 d can generally have a shape of a “V” or“U”. The lesion is transmural, for example between first upper location271 d and lower location 272 d, or between second upper location 273 dand lower location 272 d. Hence, although there may be an area ofunablated or underablated tissue between first upper location 271 d andsecond upper location 273 d, at central upper location 274 d, a truetransmural bipolar lesion is produced as the lesion is present acrossthe entire thickness of the tissue, from one surface to the opposingsurface.

As depicted in FIGS. 2A to 2D, for example, embodiments of the presentinvention include methods and systems for enfolding tissue into a recessto enhance contact or approximation between the tissue and the systemelectrodes. Hence, the transmurality of ablations delivered by thesystem can be enhanced or optimized. What is more, embodiments of thepresent invention encompass systems and methods that provide dualelectrode sets along sides of an inner recess of an ablation mechanismor suction pod, where an electrode set along one side operates as anactive electrode assembly, and an electrode set along an opposing sideoperates as a return electrode assembly.

Embodiments of the present invention also encompass systems havingvarious multiple electrode spacing schemes. For example, FIG. 3A,provides a cross-section view of a surgical system 300 a that includesan ablation mechanism 310 a having a first electrode assembly 312 a anda second electrode assembly 314 a. System 300 a also includes a suctionstabilizer mechanism 320 a coupled with or in operative association withthe ablation mechanism. As shown here, suction stabilizer mechanism 320a defines a recess 324 a having a depth D, and each of the electrodeassemblies 312 a and 314 a define a height H, such that depth D andheight H are approximately the same or equal. In some cases, depth D isabout 10 mm. In some cases, the distance between electrodes is about 10mm. Optionally, ablation probe assemblies can be configured for treatingtissues having any of a variety of widths, including for example tissuethicknesses of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, and the like.

FIG. 3B provides a cross-section view of a surgical system 300 b thatincludes an ablation mechanism 310 b having a first electrode assembly312 b and a second electrode assembly 314 b. System 300 b also includesa suction stabilizer mechanism 320 b coupled with or in operativeassociation with the ablation mechanism. As shown here, suctionstabilizer mechanism 320 b defines a recess 324 b having a depth D, andeach of the electrode assemblies 312 b and 314 b define a height H, suchthat depth D is greater than height H. At a first side of the stabilizerrecess, the stabilizer presents a recess wall 330 b having a proximalsection 332 b and a distal section 334 b. At a second side of thestabilizer recess, opposite the first side, the stabilizer presents anopposing recess wall 331 b having a proximal section 333 b and a distalsection 335 b. First electrode assembly 312 b is positioned at or nearrecess wall distal section 334 b, and second electrode assembly 314 b ispositioned at or near opposing recess wall distal section 335 b.

FIG. 3C provides a cross-section view of a surgical system 300 c thatincludes an ablation mechanism 310 c having a first electrode assembly312 c and a second electrode assembly 314 c. System 300 c also includesa suction stabilizer mechanism 320 c coupled with or in operativeassociation with the ablation mechanism. As shown here, suctionstabilizer mechanism 320 c defines a recess 324 c having a depth D, andeach of the electrode assemblies 312 c and 314 c define a height H, suchthat depth D is greater than height H. At a first side of the stabilizerrecess, the stabilizer presents a recess wall 330 c having a proximalsection 332 c, a central section 334 c, and a distal section 336 c. At asecond side of the stabilizer recess, opposite the first side, thestabilizer presents an opposing recess wall 331 c having a proximalsection 333 c, a central section 335 c, and a distal section 337 c.First electrode assembly 312 c is positioned at or near recess wallcentral section 334 c, and second electrode assembly 314 c is positionedat or near opposing recess wall central section 335 c.

FIG. 3D provides a cross-section view of a surgical system 300 d thatincludes an ablation mechanism 310 d having a first electrode assembly312 d and a second electrode assembly 314 d. System 300 d also includesa suction stabilizer mechanism 320 d coupled with or in operativeassociation with the ablation mechanism. As shown here, suctionstabilizer mechanism 320 d defines a recess 324 d having a depth D, andeach of the electrode assemblies 312 d and 314 d define a height H, suchthat depth D is greater than height H. At a first side of the stabilizerrecess, the stabilizer presents a recess wall 330 d having a proximalsection 332 d, a central section 334 d, and a distal section 336 d. At asecond side of the stabilizer recess, opposite the first side, thestabilizer presents an opposing recess wall 331 d having a proximalsection 333 d, a central section 335 d, and a distal section 337 d.First electrode assembly 312 d is positioned at or near recess walldistal section 336 d, and second electrode assembly 314 d is positionedat or near opposing recess wall proximal section 333 d.

FIG. 3E provides a cross-section view of a surgical system 300 e thatincludes an ablation mechanism 310 e having a first electrode assembly312 e and a second electrode assembly 314 e. First electrode assembly312 e includes a proximal electrode 313 e and a distal electrode 315 e.Second electrode assembly 314 e includes a proximal electrode 317 e anda distal electrode 319 e. System 300 e also includes a suctionstabilizer mechanism 320 e coupled with or in operative association withthe ablation mechanism. As shown here, suction stabilizer mechanism 320e defines a recess 324 e having a depth D, and each of the electrodes313 e, 315 e, 317 e, and 319 e define a height H1, H2, H3, and H4,respectively, such that depth D is greater than each of height H1, H2,H3, and H4. At a first side of the stabilizer recess, the stabilizerpresents a recess wall 330 e having a proximal section 332 e, a centralsection 334 e, and a distal section 336 e. At a second side of thestabilizer recess, opposite the first side, the stabilizer presents anopposing recess wall 331 e having a proximal section 333 e, a centralsection 335 e, and a distal section 337 e. Electrode 313 e is positionedat or near recess wall proximal section 332 e, electrode 315 e, ispositioned at or near recess wall distal section 336 e, electrode 317 eis positioned at or near recess wall proximal section 333 e, andelectrode 319 e is positioned at or near recess wall distal section 337e.

Any of a variety of current flow pathways and combinations of pathwayscan be implemented by providing energizing and return circuits betweenthe various electrodes. For instance, when electrodes 313 e and 317 eare configured as a circuit, for example by coupling them with a relatedpower delivery and return interfaces of an electrosurgical unit (notshown), system 300 e can provide a current flow pathway as indicated byarrow CA. When electrodes 313 e and 319 e are configured as a circuit,for example by coupling them with a related power delivery and returninterfaces of an electrosurgical unit (not shown), system 300 e canprovide a current flow pathway as indicated by arrow CB. When electrodes315 e, and 317 e are configured as a circuit, for example by couplingthem with a related power delivery and return interfaces of anelectrosurgical unit (not shown), system 300 e can provide a currentflow pathway as indicated by arrow CC. When electrodes 315 e, and 319 eare configured as a circuit, for example by coupling them with a relatedpower delivery and return interfaces of an electrosurgical unit (notshown), system 300 e can provide a current flow pathway as indicated byarrow CD. Relatedly, systems 300 e is configurable to delivercombinations of current flow pathways, for example pathway CA incombination with pathway CD, and the like. Hence, embodiments of thepresent invention encompass systems that provide multiple electrodespacing and activation schemes.

As depicted in FIGS. 3A to 3E, for example, embodiments of the presentinvention encompass systems and methods that can switch betweenmonopolar electrode capability and bipolar electrode capability. Systemsand methods may also include multiple electrode sets having opposedactive and/or return electrodes. Various structural elements of anablation mechanism, such as a ribcage assembly, a suction pod assembly,or a combination thereof can operate to allow suction or negativepressure to draw tissue into a recess and against or toward theelectrodes.

Embodiments of the present invention also encompass systems havingvarious ablation element design and shape configurations. For example,FIG. 4 shows an electrode 400 having a serpentine configuration.Exemplary electrode mechanisms can have an electrode shaped lengthwiseto allow bending and length changes. Electrode mechanisms can provideone or more electrodes shaped lengthwise in a straight, serpentine, orother shape. Hence, several electrode designs and arrays are possible,including without limitation planar electrodes, cylindrical helicalelectrodes, and linear wire/cable/strip type electrodes. According tosome embodiments, electrode configuration can provide a screen mechanismwhereby suction provided by a vacuum source can be transmittedtherethrough, for application to a patient tissue.

In some instances, tissue treatment systems can include one or moretemperature sensors for detecting the temperature at selected locations.FIG. 5 illustrates a cross-section of a surgical system 500 according toembodiments of the present invention. System 500 includes an ablationmechanism 510 having a first electrode assembly 512 and a secondelectrode assembly 514. System 500 also includes a suction stabilizermechanism 520 coupled with or in operative association with the ablationmechanism. As shown here, system 500 further includes a firsttemperature sensor, such as a thermocouple TC1, in operative associationwith first electrode assembly 512, and a second temperature sensor, suchas thermocouple TC2, in operative association with second electrodeassembly 514. For example, thermocouples TC1 and TC2 can be in thermalcontact with electrodes 512 and 514, respectively. System 500 alsoincludes a third temperature sensor, such as thermocouple TC3, locatedat a central recess wall portion 560 of suction stabilizer mechanism520.

When ablation mechanisms or electrodes 512 and 514 are configured as acircuit, for example by coupling them with a related power delivery andreturn interfaces of an electrosurgical unit (not shown), system 500 canprovide a current flow pathway as indicated by arrows A. Current passingthrough this section B of the patient tissue causes an increase intissue temperature, due to ohmic heating and the electrical resistanceproperties of the tissue. The system is configured such that currentpassing through the ablation elements 512, 514 does not directly lead toan increase in electrode temperature. Changes in temperature sensed bythe temperature sensors TC1, TC2, TC3 are due to heat conducted from theheated tissue to the sensors. Section C, and relatedly temperaturesensor TC3, are at the coolest identifiable or measurable location.There is less current density flowing through section C of the patienttissue as compared with the directly heated tissue at section B. SectionC is furthest from the directly heated tissue at section B, and theincrease in temperature at section B precedes the increase intemperature at section C. In some instances, the temperature atthermocouple TC3 or section C can be used to confirm or assess thestatus of a transmural ablation, while the temperature at thermocouplesTC1 and TC2 (which is higher than the temperature at thermocouple TC3)can be used for controlling amounts of the energy delivered betweenelectrodes 512 and 514. Relatedly, the temperature at thermocouple TC3or section C can be used to confirm that a transmural lesion has beencompleted. For example, if temperature sensor TC3 indicates atemperature of 60° Celsius at tissue section C, it is possible toconclude that the temperature at tissue section B is 60° Celsius orhigher (e.g. 80° Celsius). Because transmural lesions in atrial tissueoften occur where the tissue is heated above 50° Celsius across the fullthickness of the tissue, a reading of 60° Celsius at temperature sensorTC3 can be considered to signal the successful formation of a lesion.Embodiments of the present invention also encompass systems havingthermal sensors positioned at various locations on or within the system.

According to some embodiments, systems can include stimulationmechanisms for pacing or sensing mechanism for evaluating resistivity.FIG. 5A illustrates a cross-section of a surgical system 500 a accordingto embodiments of the present invention. System 500 includes an ablationmechanism 510 a having a first electrode assembly 512 a and a secondelectrode assembly 514 a. System 500 a also includes a suctionstabilizer mechanism 520 a coupled with or in operative association withthe ablation mechanism. As shown here, system 500 a further includes afirst temperature sensor, such as a thermocouple TC1, in operativeassociation with first electrode assembly 512 a, and a secondtemperature sensor, such as thermocouple TC2 a, in operative associationwith second electrode assembly 514 a. System 500 a includes a thirdtemperature sensor, such as thermocouple TC3, located at a centralrecess wall portion 560 a of suction stabilizer mechanism 520 a. System500 a also include a transmission element 540 a. In some instances,transmission element 540 a can include a small surface area electrodefor placement at or near location C to enable pacing or to be used tosense local tissue resistivity. The transmission element could include aspot electrode having a diameter of about 2 mm, or it could include athin elongate wire or electrode strip that is the same length as theablation electrodes 512 a and 514 a. In some instances, transmissionelement 540 a may be narrower than the ablation electrodes. For example,transmission element may have a diameter within a range from about 0.5mm to about 1.5 mm.

Prior to the application of an ablation, transmission element 540 a canbe used in a pacing mode to determine if the patient tissue was drawnsufficiently far enough into the stabilizer channel, so thattransmission element 540 a contacts region C of the patient tissue. Ifthe transmission element can not pace the heart using 20 Volt 1 msecwide pacing pulses, then it is possible to conclude that contact betweenthe transmission element and the patient tissue has not been establishedand the success of the ablation is less likely. Typically, pacing is anall-or-none phenomenon, and stimulation of just a few cells at asufficiently high local voltage gradient leads to stimulation of thesurrounding tissue due to the propagation properties of the tissue. Whencontact is established, which may be observed by a pacing response asthe stimulation is propagated through the tissue, a baseline resistancereading using a frequency of 50 kHz to 500 KHz can be taken from thetransmission element to electrodes 514 a and 512 a. All other factorsbeing equal, tissue resistivity decreases by 2%/° C. Since the measuredresistance is primarily dependent on the resistivity within 1-2 mm oftransmission element 540, the measured resistance provides an estimateof the weighed-average temperature of tissue near the transmissionelement. The weighted average is inversely proportional or related tothe current density. The weighted average can be used to determine anaverage temperature along the entire contacted region, and hence theresistivity provides a distributed measurement parameter of temperature.A reduction of 35% from baseline indicates that the local tissuetemperature is about 60° C., and is a good indication that lesiontransmurality is achieved. Such spatial heat averaging techniques can beused to determine current density in tissue, as a change in resistivityis reflective of what is occurring in the tissue locally.

In some instances, the cross-section of transmission element 540 may becircular. Optionally, transmission element 540 may include a spotelectrode or a thin wire or layer of conductive material for pacing orimpedance sensing. Optionally, transmission element 540 may be equal inlength to that of either or both of the electrode assemblies. Thetransmission element can be sized so that in use it samples only tissuethat is positioned relatively near to it. Typically, the tissue closestto the transmission element, for example within about one to twomillimeters of the transmission element, provides a significantpercentage of the resistivity measured. System 500 can be used toperform pacing techniques such as those described in U.S. patentapplication Ser. No. 12/463,760 filed May 11, 2009, the content of whichis incorporated herein by reference.

According to some embodiments, the pacing technique can allow thetransmission element 540 to operate as a contact sensor. Hence, if asufficiently high pacing voltage is applied through the transmissionelement such that contact between the transmission element and tissuewill likely result in a stimulation response, then the presence of sucha stimulation response can be used as an indication of contact betweenthe transmission element and the tissue. In the absence of contact, forexample where the transmission element and the tissue are separated by adistance of 0.1 mm or 0.01 mm, there will not be enough current passinginto the tissue so as to generate a stimulation response.

Generally, resistivity can provide an accurate measurement oftemperature, particularly where the tissue remains sufficientlyhydrated. Excessive temperatures may cause tissue to lose hydration,however. Because transmission element 540 is positioned along the tissueat a relatively cool location at section C, away from electrodeassemblies 512 a and 514 a, there is less loss of hydration and hencethe accuracy of the temperature measurement remains high during theapplication of an ablation treatment when tissue section B is heated tocreate a lesion.

Moreover, because this technique provides a ratiometric measurement, aslong as the tissue at section C does not significantly change during themeasurement period, even if there was some degree of drying or charthere prior to ablation, it will not impact the impedance measurement;the percentage change in resistivity provides a good reflection of thetemperature change in the sample tissue during a particular ablationapplication, and the lesion confirmation functionality of transmissionelement 540 remains viable.

Surgical systems such as treatment system 500 can include any desirednumber of active and return electrodes. For example, surgical systemscan include 6 or 7 active electrodes and 1 or 2 inactive electrodes.Systems can be configured to deliver various types of regulated energydelivery, such as RF energy which is controlled by maintaining a settissue temperature. Temperature sensors can be placed at multiplelocations along the length and cross-section of the device, for examplein close contact with the active ablating electrode(s) and along thecenter line of the roof of the suction stabilizer to provide anindication of temperature at the tissue center away from ablation.

With reference to FIGS. 5 and 5A, for example, and as further disclosedherein, exemplary systems and methods provide ablation functions, pacingfunctions, and combinations thereof, at multiple locations along thesame or opposing walls of a suction pod or ribcage mechanism. In someinstances, treatment systems may include a temperature sensor inoperative association with a return electrode. In some instances,treatment systems may include a temperature sensor disposed along acentral inner recess. In some instances, treatment systems may include atemperature sensor in operative association with an active electrode.

In some instances, tissue treatment systems can include one or morecooling or irrigation mechanisms for cooling or irrigation of selectedsystem features. For example, a surgical system may include an ablationmechanism having a first electrode assembly and a second electrodeassembly. The system may also include a suction stabilizer mechanismcoupled with or in operative association with the ablation mechanism.Moreover, the system may include multiple cooling or irrigation lumens,such as first, second, and third cooling or irrigation lumens,respectively. Such lumens can be, for example, formed as open or closedchannels along suction stabilizer mechanism. Saline or other fluid canbe transmitted through the lumens to accomplish cooling or irrigation ofthe device, the patient tissue, or both. In some instances, fluidpassing through a first lumen can help to regulate the temperature of afirst electrode, and fluid passing through a second lumen can help toregulate the temperature of a second electrode. Fluid passing through oralong lumens or channels can help to irrigate or regulate thetemperature of patient tissue T.

FIG. 6A depicts aspects of a surgery system 600 a according toembodiments of the present invention. Such systems are well suited foruse in epicardial transmural ablation procedures, including bipolarablation approaches. As shown in this probe assembly cross-section, thesystem includes a membrane or pod mechanism 610 a that encases a ribcagemechanism 640 a therein. The probe assembly provides a hinge point 620 aabout which the membrane and ribcage may flex. In some instances, aprobe assembly may include a web mechanism 650 a having a porous,elastic or non-elastic, flexible material that bridges a span betweenthe suction pod arms or electrode arms. As tissue is drawn into theprobe assembly and between the arms, the web mechanism 650 a is drawn inas well, thus pulling the arms together, for example until a fold iscreated in the tissue.

As shown in FIGS. 6B and 6C, and as with other embodiments disclosedherein, the probe assembly 605 a allows the electrodes to be inapposition to tissues having a variety of thicknesses (e.g. thick tissueas shown in FIG. 6B, or thin tissue as shown in FIG. 6C), and can beused to create transmural lesions without epicardial lesion gaps orexcessively wide lesions. The dotted lines 615 a within the tissuerepresent current flow through the tissue. When the tissue is releasedfrom the probe assembly 605 a, the tissue is thereafter provided with atransmural lesion. As shown in FIG. 6D, a flexible ribcage mechanism 640a can have individual fingers or ribs that can bend or flex eithertoward or away from the center of the ribcage, thus enabling the ribcage640 a to accommodate tissues of varying thickness and to provide widthadjustability along its length.

In some instances, surgical systems may include ribcage mechanisms,suction pod mechanisms, or both, having active side walls, wheremovement of the ribcage and/or suction pod side walls can be driven bymechanisms other than suction. For example, clamping mechanisms may beused to actuate the side walls, thereby releasing or applying clampingpressure to tissue disposed between the opposing electrodes or ribs. Insome cases, a surgical system may include lengthwise clamps or tongsdisposed along the exterior of opposing sides of a suction podmechanism, whereby such clamps or tongs can actuate to squeeze tissuebetween the suction pod side walls. In some cases, beating heart tissuecan be drawn by suction into the a probe suction chamber or recess, andcan conform to a degree to the confines of the chamber or recess,between the ribcage sidewalls or ablation electrodes. In some cases, theelectrodes are shaped to follow the geometry of the infolded tissue,thus enhancing contact between the electrodes and the tissue. Forexample, electrodes may be curved, straight, angled inward at the top,or otherwise configured to both conform to and help shape the infoldingtissue. In some cases, a ribcage mechanism may include a central spine,with ribs disposed either inside or outside of a suction pod. Asindicated above, FIGS. 6A to 6D depict aspects of a treatment systemthat delivers a bipolar epicardial transmural ablation, according toembodiments of the present invention. As shown here, the system presentshinge points, and includes electrodes and a membrane that encases thestructure to seal a vacuum within. The system also includes a veryporous, non-elastic, flexible web material that forms a bridge betweenthe flexible electrode arms. As tissue is drawn between the arms, theweb material is drawn in as well, and the arms are pulled together untila tissue fold is created. Such embodiments allow electrodes to be inapposition to various thickness of tissue so as to create a transmurallesion without an epicardial lesion gap or an excessively wide lesion.In the upper panels showing the pinched thick and thin tissues, thedotted lines represent current flow through tissue. When tissue isreleased, the lesion is transmural. These embodiments allow for overallflexibility, including upward, downward, and sideways movements. In someinstances—individual electrode fingers can enable the treatment ofvarying tissue thicknesses, and provide adjustability along the lengthof the device. The system can be configured as a short connecting lesiondevice as described with reference to FIG. 13, or as a long loop deviceas described with reference to FIG. 14. The system can accommodatediffering thicknesses of tissue, and further, can accommodate differentthickness of tissue in the same bite or clamping step where tissuethickness changes along the length of the system.

As depicted in FIGS. 7 to 7B, embodiments of the present inventionencompass systems that provide a pocket, recess, cavity, or channel,which may be defined by a suction pod, ribcage mechanism, or both, intowhich tissue can be drawn. Relatedly, as shown in these drawings,embodiments provide techniques for drawing tissue into such recesses,optionally with the use of suction, and against or toward electrodemechanisms which are positioned therein. In some instances, such acavity can be presented along the entire length, or a portion of theentire length, of a suction pod mechanism. Hence, the system can providesuction to the tissue along the full length, or a portion of the fulllength, or an electrode mechanism. Further, embodiments of the presentinvention encompass systems and methods that provide for the applicationof either monopolar ablation energy, or bipolar ablation energy, or acombination thereof. For example, in use, the system may be switchedback and forth between a monopolar electrode capability and a bipolarelectrode capability. In some instances, one or more temperature sensorsmay be located along a central inner recess of a suction pod mechanism.

Embodiments of the present invention encompass systems and methods thatinvolve the combined or bimodal application of bipolar and monopolarablation protocols. FIG. 7 shows a surgical system 700 that includes anablation mechanism 710 having a first electrode assembly 712 and asecond electrode assembly 714. System 700 also includes a suctionstabilizer mechanism 720 coupled with or in operative association withthe ablation mechanism. As shown here, suction stabilizer mechanism 720defines a recess or cavity 724 into which patient tissue can be drawn,for example by creating a vacuum or introducing a relative negativepressure within the recess. As depicted here, system 700 includes or isin operative association with a vacuum source 790, which is in fluidcommunication with a vacuum port or aperture 792 via a vacuum line orpassage 794. When electrodes 712 and 714 are configured as the onlyelectrodes in the circuit serving as active and return electrodesrespectively, for example by coupling them with a related power deliveryand return interfaces of an electrosurgical unit (ESU) 780, system 700can provide a bipolar current flow pathway as indicated by arrows B.When electrode 712 serves as the active electrode and a ground pad 770serves as the return electrode, for example by coupling electrode 712and ground pad 770 with related power delivery and return interfaces,respectively, of ESU 780, system 700 can provide a monopolar currentflow pathway as indicated by arrows M. Conversely, it is understood thatelectrodes 712 and 714 can be operated as return and active electrodes,respectively, in an alternative bipolar configuration, and thatelectrode 714 can operate as an active electrode and ground pad 770 canoperate as a return mechanism, in an alternative monopolarconfiguration.

As shown in FIG. 7A, when electrodes 712 and 714 both serve as activeelectrodes and ground pad 770 serves as a return electrode, for exampleby coupling electrodes 712 and 714 with an ESU power delivery interfaceand ground pad 770 with an ESU return interface, system 700 can providea monopolar current flow pathway as indicated by arrows M1, where thecurrent paths come from both active electrodes and flow toward theground pad. In contrast with the monopolar flow shown in FIG. 7, whenboth electrodes are active as depicted in FIG. 7A, current from each ofthe electrodes is less focused toward the intervening location betweenthe electrodes, and more strongly directed toward paths that extenddownward and across the full tissue wall, due to the propensity of thecurrent to maintain separate flow paths and travel toward areas of lowerpotential. Hence, the upper central portion of tissue D typically willbe cooler during the dual active electrode monopolar modality shown inFIG. 7A, as compared with the bipolar modality. Relatedly, heating ofsection D during bipolar ablation will be primarily due to directheating or conduction which is proportional to the square of the currentdensity locally, whereas heating of section D during dual activeelectrode monopolar ablation will be primarily due to conduction.

Patient tissue that is not drawn into the suction stabilizer chamber ortrough can be heated more effectively when current is flowing downwardtoward the ground pad during monopolar ablation, because it is lesslikely that tissue will be ablated during bipolar ablation where lesionformation occurs primarily between the electrodes within the suctionstabilizer trough. Hence, for tissue outside of the suction stabilizerrecess, monopolar current provides more heating to that tissue. Bipolarablation may provide heat to this tissue outside of the stabilizer, butthis is due to approximation conduction, where heat flows from thehotter tissue within the stabilizer recess to tissue outside of therecess. In contrast, monopolar ablation can deliver direct heating forthis tissue.

Heat convection can play a significant role in tissue ablation and thesize of the resulting lesion during monopolar and bipolar radiofrequencytreatments. For example, for monopolar ablations, heat convection may beresponsible for about 90% of the lesion. Similarly, for bipolarablations, heat convection may be responsible for about 67% of thelesion. The process of heat convection can also facilitate thecontinuous or cumulative administration of ablation energy, as heat isconvected away from the electrode where the most intense direct tissueheating occurs, and into other nearby tissue.

As tissue is drawn into the suction stabilizer channel, the tissue maybe distorted. As shown in FIG. 7B, a section of tissue having a depth ofd1 is drawn into the channel, leaving a corresponding tissue divot orrecess having a depth of d2. In some instances, depth d1 may be twice aslarge as depth d2. Hence, if tissue is drawn into the stabilizer recessto a depth d1 of about 1 cm, the corresponding divot on the opposingside of the tissue may have a depth d2 about 0.5 cm. Similarly, thesection of tissue drawn into the channel can have a width of w1, leavinga corresponding tissue divot or recess having a width of w2. In someinstances, width d2 may be twice as large as width d1. Hence, if tissueis drawn into the stabilizer recess such that width w1 is about 0.5 cm,then the corresponding divot on the opposing side of the tissue may havea width w2 about 1 cm.

During ablation a thermal boundary layer can form along the surface ofthe tissue opposing the ablation electrodes. For example, as illustratedin FIG. 7B, a boundary layer BL may form along an inner section of theatrial tissue. In some cases, the boundary layer may have a thickness ofabout 1 mm, and due to convective cooling within the heart, the tissuetemperature at boundary layer may be maintained at about 37 degreesCelsius. The phenomenon of convective cooling also may make it difficultto sufficiently heat the boundary layer BL of patient tissue. Not onlyis blood conductively removing heat from the boundary layer due tocontact proximity, but blood is also convectively removing heat from theboundary layer as it flows away due to circulation. As the velocity ofblood flowing along the boundary layer increases, the thickness of theboundary layer becomes smaller, and the thickness of tissue being heatedprimarily by conduction increases. When tissue has been drawn into thesuction stabilizer channel so as to create a divot or recess on theopposing side of the tissue, typically there is less blood flow ormovement within the resulting tissue recess, and blood tends to remainthere. Hence, the effect of convective cooling by blood at the boundarylayer BL is reduced.

With continuing reference to FIGS. 7 and 7A, the ablation accomplishedby monopolar current M or M1 is localized in an area adjacent to theactive electrode or electrodes, where the current density is higher. Dueto dissipation effects, monopolar current does not ablate tissue as ittravels farther beyond this area toward the ground pad. When in thebipolar configuration, the ground pad can be disconnected orelectrically disassociated from the ESU, and when in the monopolarconfiguration, electrode 712 or 714 (FIG. 7) can be disconnected orelectrically disassociated from the ESU. In some cases, bipolar currentB and monopolar current M or M1 are applied simultaneously during atreatment. Ground pad 770 can be affixed or placed against an externalportion of the patient's body. For example, the ground pad can beadhered to skin tissue on the patient's back. In some cases, a groundpad or mechanism 770 can be placed at a desired location within thepatient's anatomy. As illustrated here, line 782 provides connectivitybetween the ESU and electrode 712, line 784 provides connectivitybetween the ESU and electrode 714, and ground line 772 providesconnectivity between ground pad 770 and the ESU. By using a ground padit is possible to achieve a certain type of tissue burn or ablation.Conversely, by not using a ground pad it is possible to achieve adifferent type of tissue burn or ablation. With reference to FIG. 7, itcan be seen that the application of monopolar current flow, as indicatedby arrows M, can be helpful in achieving transmural ablations, forexample when treating tissues having greater thicknesses. Without thisadditional monopolar ablation, in some cases the tissue may be too thickto accomplish transmural lesions with bipolar energy between electrodes712 and 714 alone, because although the top layer of tissue issufficiently drawn into the suction stabilizer recess, the lower layerof tissue may remain extending outside of the recess, and thereforereceive insufficient energy from the delivered ablation energy so thattissue ablation is not achieved as desired.

When bipolar and monopolar ablation is applied simultaneously, somecurrent passes from the active electrode (e.g. 712) to the returnelectrode (e.g. 714), and some current passes from the active electrode(e.g. 712) to ground pad 770. As noted above, such bipolar and monopolaradministration of ablation energy can be applied in an alternatingfashion. For example, the ground pad can be unplugged or electricallydissociated from the ESU for application of bipolar energy. Similarly,the return electrode can be unplugged or electrically disassociated fromthe ESU for application of monopolar energy. In some cases, the ESU mayalso be referred to as a generator or a control box.

According to some embodiments, ablation treatment may switch rapidlybetween a bipolar ablation and a monopolar ablation during a single RFablation application. For example, an ESU can be configured toautomatically change modes between bipolar and monopolar modes, withinthe course of a treatment. Such switched ablation protocols can beeffective in creating tissue lesions. In some cases, switching may occurat 15 second intervals or faster. In some instances, switching may occuras fast as 0.1 second intervals. Various ablation mode protocols aredescribed in Table 1. As shown here, a treatment system can be switchedbetween any of a variety of bipolar and monopolar operating modes.

TABLE 1 Electrode 712 Electrode 714 status status Pad 770 statusAblation Mode switched to active switched to active switched to returndual electrode monopolar switched to active switched to return switchedoff bipolar (712 to 714) switched to return switched to active switchedoff bipolar (714 to 712) switched to active switched off switched toreturn monopolar (from 712) switched off switched to active switched toreturn monopolar (from 714) switched to active switched to returnswitched to return combined bipolar and monopolar switched to returnswitched to active switched to return combined bipolar and monopolar

When switched to an active configuration, an electrode is typically inoperative association with an active channel of the ESU. Similarly, whenswitched to a return configuration, an electrode or pad is typically inoperative association with a return channel of the ESU. When switchedoff, an electrode or pad can be disassociated from the active and returnchannels. With regard to any of the ablation modes, the power or energydelivered to each electrode can be feedback controlled based onelectrode temperature. In some instances, switching can be performed byprocessors, electronic circuits, software, firmware, or any combinationthereof.

In some instances, embodiments of the present invention encompasssystems and methods which counteract or overcome a heat sink effect,which can be caused by relatively cool blood drawing heat away from thetissue. FIG. 8 shows a surgical system 800 that includes an ablationmechanism 810 having a first electrode assembly 812 and a secondelectrode assembly 814. System 800 also includes a suction stabilizermechanism 820 coupled with or in operative association with the ablationmechanism. As shown here, suction stabilizer mechanism 820 defines arecess 824 into which patient tissue can be drawn, for example bycreating a vacuum or introducing a relative negative pressure within therecess. When the tissue is pulled into recess 824, it bunches andbecomes more uniformly compressed. The portion of the tissue beingablated is drawn out of the blood stream, or otherwise thermallyisolated from the heat sink effect caused by the blood. Hence, heatgenerated within the tissue via application of current is not dissipatedinto the blood stream, and consistent temperatures are maintained withinthe treated tissue. As depicted in FIG. 8, a suction pod mechanism orribcage mechanism can provide a pocket, recess, cavity, or channel, intowhich tissue can be drawn. Relatedly, as shown here, embodiments providetechniques for drawing tissue into such recesses and against or towardelectrode mechanisms which are positioned therein. In some instances,systems include one or more temperature sensors in association with anelectrode, such as an active electrode.

Accordingly, as shown in the FIG. 8 cross-section, tissue can be drawnand folded into the recess 824 between electrodes 812 and 814, and thefolded tissue can be ablated. In some instances, the tissue is folded soas to provide a valley 830 that runs along the length of a probeassembly. Hence, there is a continuous and linear tissue apposition,whereby two sections of the same tissue are positioned in a side-by-sidemanner. In this way, the surgical system facilitates the formation of anoverall continuous lesion. As depicted in FIG. 8A, an ablation probeassembly 810 a can be configured with electrodes 812 a, 814 a that aredisposed near the recess entrance, such that treatment of the tissueresults in a lesion pattern having two parallel lines or sections (e.g.when the tissue is removed from the recess and unfolds). In comparison,a probe assembly and treatment configuration as shown in FIG. 8 canresult in a single lesion line or section having a trapezoidalcross-section, with a wider length along the endocardial surface and anarrower length along the epicardial surface. Hence, depending on thegeometry of the ablation probe assembly, the thickness of the tissue, ora combination of both, there may be two parallel lines epicardially andendocardially (e.g. FIG. 8A), or two parallel lines epicardially andonly one endocardially (e.g. FIGS. 2D, 6B). Relatedly, in someembodiments, because of conductive heating, the lesion may spreadsomewhat beyond the electrode contact surface area and the twoepicardial lines may merge into one. Generally speaking, clinically awider lesion may create a more permanent conduction block; one reasonbeing that any healing, live cell in-growth into the lesion scar, and/orremodeling over time is less likely to bridge a wider gap. In this way,two parallel ablated lines or wider ablation lesions can provide asafety feature, and relatedly, where there are double ablation lines,one lesion can compensate for a possible gap (if such occurs) in otherlesion.

FIG. 9 illustrates a surgical system 900 that includes an ablationmechanism 910 having a first electrode assembly 912 and a secondelectrode assembly 914. System 900 also includes a suction stabilizermechanism 920 coupled with or in operative association with the ablationmechanism. Suction stabilizer mechanism 920 defines a recess 924 intowhich patient tissue can be drawn, for example by creating a vacuum orintroducing a relative negative pressure within the recess. As shownhere, suction stabilizer 920, optionally in combination with anelectrode, can provide or define recess 924 or integral lumens 950, 960to help channel the vacuum or negative pressure and draw tissue intocontact with the electrodes. Such pockets, lumens, or other surfacecontours or features along the inner wall or ceiling of the suctionstabilizer recess, can help facilitate the administration of a vacuum ornegative pressure along a desired length of the suction stabilizer, forexample by preventing or inhibiting fluid flow blockages from developingat a proximal portion, which could diminish the opportunity for applyinga vacuum or negative pressure at a more distal portion of the device.

Embodiments of the present invention encompass systems and methods whichhelp to deliver and maintain vacuum or negative pressure along a lengthof the suction stabilizer. In some instances, embodiments provide anablation mechanism having a first electrode assembly and a secondelectrode assembly, and a wide stabilizer mechanism or ribcage mechanismwith a low, perforated ceiling. When vacuum or negative pressure isdelivered via a port, tissue is drawn into channel. The tissue isprevented from contacting the vacuum port or entering a vacuum track,due to the presence of the perforated ceiling. In this way, the ceilingmay operate as a screen. Hence, a vacuum or negative pressure can bemaintained within a vacuum track without disruption from the tissue. Insome instances, a perforated ceiling may include a plastic sheet havinga thickness of about 0.5 mm, with multiple holes or apertures. In someinstances, such perforations, apertures, or gaps may be an integral partof a ribcage mechanism. For instance, a ribcage mechanism may have aribcage spine with a serpentine shape, and intercostal or alternatingspaces between the serpentine loops provide such apertures or gaps alongthe length of the ribcage mechanism. A ribcage mechanism presenting afishbone configuration can also provide such gaps or apertures.

In some instances, systems may include an ablation mechanism having afirst electrode assembly and a second electrode assembly, and astabilizer mechanism with a screen ceiling. When vacuum or negativepressure is delivered via a port, tissue is drawn into a trapezoidalchannel. The tissue is prevented from contacting a vacuum port orentering a vacuum track, due to the presence of the screen ceiling.Hence, a vacuum or negative pressure can be maintained within vacuumtrack without disruption from the tissue. In some cases, electrodeassemblies may include angled electrodes. In some instances, a systemmay include a narrow stabilizer mechanism.

FIG. 10 illustrates a surgical system 1000 that includes an ablationmechanism 1040 having a first electrode assembly 1042 and a secondelectrode assembly 1044. The electrode assemblies can be coupled with orin operative association with a ribcage mechanism 1050. In someinstances, the ablation mechanism 1040 is considered to include orincorporate the ribcage mechanism 1050. System 1000 also includes asuction stabilizer mechanism or pod 1060 coupled with or in operativeassociation with the ablation mechanism. Suction stabilizer mechanism1060 defines a recess 1030 into which patient tissue can be drawn, forexample by creating a vacuum or introducing a relative negative pressurewithin the recess. As shown here, suction stabilizer 1060, optionally incombination with an electrode and/or a ribcage mechanism, can provide ordefine recess 1030 and/or other open spaces or lumens 1010 disposedbehind the ribcage and/or electrodes, so as to help channel the vacuumor negative pressure and draw tissue into contact with the electrodes.Such pockets, lumens, or other surface contours or features along theinner wall or ceiling of the suction stabilizer recess, can helpfacilitate the administration of a vacuum or negative pressure along adesired length of the suction stabilizer, for example by preventing orinhibiting fluid flow blockages from developing at a proximal portion,which could diminish the opportunity for applying a vacuum or negativepressure at a more distal portion of the device. Hence, the ribcagemechanism 1050 can provide apertures, rib spacings, or openings 1020,such that when suction is applied, the vacuum or relative negativepressure is transmitted from the open spaces or lumens 1010, through theopenings 1020, and into the recess 1030, where the suction or relativenegative pressure operates to draw tissue into the recess as indicatedby arrow 1025. Put another way, the suction can operate to evacuate airor fluid from the recess 1030, by virtue of the openings 1020 providedby a porous screen or portion or slotted structure of the ribcagemechanism 1050. Accordingly, tissue is pulled or drawn into contact withelectrodes 1042 and 1044. According to some embodiments, the ribcagemechanism 1050 also provides a degree of structural rigidity, so as tohelp maintain the recess 1030 as a non-collapsible space when suction isapplied. In this way, the ribcage structure 1050 can provide a screen orporous portion for transmitting the suction, and can also help tomaintain the volume and geometry of the recess 1030 when the suction isapplied.

In some embodiments, a surgical system may include a probe assemblyhaving a non-adjustable length that can be used to form a full boxlesion loop. In some embodiments, a surgical system may include a probeassembly having an adjustable length that can be used to form a full boxlesion loop. In some embodiments, a surgical system may include acinching mechanism that operates to adjust the size of a working area ofthe probe assembly. Such cinching techniques can be used to form fullbox lesion loops as well. Any of the surgical systems disclosed herein,including those providing full length probe loops and partial lengthprobe loops, can also be used to create connecting lesions.

FIG. 10A depicts aspects of a cinching mechanism and method according toembodiments of the present invention. As shown here, surgical system1000 a includes a flexible tubing mechanism 1010 a in operativeassociation with a probe assembly 1020 a (e.g. a long probe assembly asdepicted in FIG. 14), for example via a U-joint mechanism or couplingmechanism 1030 a. As described elsewhere herein, probe assembly 1020 amay include an elastic pod assembly, a flexible or semi-flexible ribcagemechanism, and an electrode assembly. As depicted here, probe assembly1020 a includes one or more apertures, holes, or lacing mechanisms (e.g.loops or hooks) 1022 a disposed at a distal portion 1024 a of the probeassembly, and one or more apertures, holes, or lacing mechanisms (e.g.loops or hooks) 1032 a disposed at a proximal portion 1034 a of theprobe assembly. In use, these lacing mechanisms 1022 a, 1032 a can bethreaded with a suture or string 1050 a (e.g. looping through aperturesor hooks, in any imaginable sequence). The two loose ends of the suturecan be threaded through a shaft or flexible tube 1060 a and when pulled(e.g. arrow A) with counter-traction on the tube (e.g. arrow B), so asto cinch the ends of the probe together (e.g. arrows C). The tube canthen be clamped off Rommel style with forceps 1070 a so that thecinching remains tight. Hence, as depicted here, a long ablationassembly with eyelets on distal and proximal ends can be used with acinching mechanism, for example a suture (or a pair of sutures) and atube. The suture or sutures can be threaded through a flexible tube,then between the eyelets (in any imaginable sequence), then back throughthe flexible tube. As the tube is advanced and the loose ends of thethreads are retracted, the proximal and distal ends of the ablationassembly are drawn together. When suction and satisfactory position isachieved, a clamping instrument can be clamped across the flexibletubing, securing and locking the suture within in its tensionedposition, maintaining the cinched condition of the ablation assembly.Releasing the clamping instrument releases the suture which can bepulled out at will.

FIG. 11 depicts a surgical system 1100 according to embodiments of thepresent invention. Surgical system 1100 includes a probe assembly 1130making a partial loop around an anatomical structure or tissue 1125 of apatient. The probe assembly 1130 provides a suction opening or recessthat can be engaged with a portion of the tissue, thereby forming atreatment zone or area 1120 where electrodes 1135 can deliver energy tothe tissue, thus forming an ablation. As shown here, a proximal portion1145 of the probe assembly 1130 can be held in place (e.g. in contactwith the patient tissue) or otherwise maneuvered by adjusting a tubingassembly 1150. For example, the tubing assembly 1150 can be used torotate the proximal end 1145 axially into a desired orientation. In somecases, the tubing assembly 1150 is coupled with the probe assembly 1130via a U-joint as discussed elsewhere herein. Further, as shown here, adistal portion 1115 of the probe assembly 1130 can be held in place(e.g. in contact with the patient tissue) or otherwise maneuvered byadjusting an introducer mechanism 1105. In some cases, the introducermechanism 1105 is coupled with the probe assembly 1130 via a magneticcoupling assembly as discussed elsewhere herein. For example, the distalportion 1115 can be held in place by tension and rotationally by amagnetic coupling to the introducer 1105. As depicted here, probeassembly 1130 includes suction stabilizer pod mechanism 1160, ribcagemechanism 1170, and electrodes 1135. Ribcage mechanism 1170 can providerib spaces 1140 between ribs of the ribcage mechanism, and these spacescan facilitate or allow contraction of the suction surface or treatmentarea 1120 without buckling of the suction pod mechanism or membrane1160. In operation, the probe assembly 1130 can be used to createmultiple lesions on the patient tissue. For example, the probe assembly1130 can be placed in a first position on the patient tissue, and energycan be delivered to form a first lesion. Thereafter, the probe assembly1130 can be placed in a second position on the patient tissue, andenergy can be delivered to form a second lesion. In some instances, allactive electrodes of the probe assembly can be activated to deliver anablation. In other instances, a subset of the active electrodes of theprobe assembly can be activated to deliver an ablation. In some cases, anumber of electrodes can be activated to deliver an ablation which formsa lesion having a first length. In some cases, a number of electrodescan be activated to deliver an ablation which forms a lesion having asecond length. In some instances, the lesion having the first length islonger than the lesion having the second length. A probe assembly 1130may be provided as a longer length mechanism. For example, probeassembly 1130 may have a length that is within a range from about 15 cmto about 30 cm. Relatedly, probe assembly 1130 may have a lengthsufficient to encircle cardiac tissue about the pulmonary veins of apatient. In some cases, a probe assembly 1130 may be provided as ashorter length mechanism. For example, probe assembly 1130 may have alength that is less than 15 cm in length. Relatedly, probe assembly 1130may have a length that is within a range from about 6 cm to about 15 cm.In some instances, a probe assembly 1130 may have a length that is about10 cm. FIG. 11A shows a probe assembly 1100 a of a surgical systemapplied to a tissue surface T. As depicted here, the probe assembly 1100a can bend, flex, and twist to conform with any irregular tissuegeometry. Relatedly, a probe assembly 1100 b can bend or flex in an XZplane as depicted in FIG. 11B-1, in an XY plane as depicted in FIG.11B-2, and/or any other plane illustrated by example in FIG. 11B-3. Asdepicted by arrows A and B of FIGS. 11B-1 and 11B-2, respectively, aprobe assembly can also twist or undergo torsion about its longitudinalaxis, optionally while bending or flexing at the same time. In somecases, a first portion of the probe assembly may bend with an a y-axisbending moment (either positive or negative) for example as shown inFIG. 11B-1, and a second portion adjacent the first portion may bendwith a z-axis bending moment (either positive or negative) for exampleas shown in FIG. 11B-2. Relatedly, such first and second portions mayalso undergo twisting, either in the same direction (e.g. right handed),or in opposing directions (e.g. first portion with left hand twist, andsecond portion with right hand twist). Such bending and twisting can beachieved by the flexible nature of the probe assembly components. Forexample, elements of a probe assembly, such as a suction pod mechanism,a ribcage mechanism, or an electrode mechanism, can be torsionallyflexible and flexurally flexible, either alone, or when present in anycombination thereof. Accordingly, the suction surface of a probeassembly can be positioned in any desired out-of-plane orientation.Because a probe assembly can flex up, down, and side to side, and canalso twist while bending, it is possible for a probe assembly toaccommodate a suction surface to any of a variety of tissue curvatures.The path around the left atrium, for example, is generally circular butbends and twists slightly out of plane around the associated anatomicalstructures. Even if these were ignored there is another combination bendand roll requirement of the probe as follows: Relatedly, because of thehemispherical shape of the atrium, an ablation probe may twist along itslength as if it were suctioned onto a wide cone shape, where the probeassembly is bent into a circular shape while twisting the suction planealong its full length slightly to one side.

Embodiments of the present invention further encompass systems andmethods for pacing patient tissue. In some instances, systems include amultifunction cable connector, which may connect various electricalcomponents of the system with an electrosurgical unit (ESU). FIG. 12shows an exemplary ablation device connector 1200 having one or morepins 1210 configured to interface with a generator or ESU (not shown).Device connector 1200 may include specific pins 1210 a, 1210 b thatconnect with pacing electrodes or leads on a treatment device, fordelivering a pacing treatment from the generator to the patient.Optionally, systems and methods may include the use of an adapter 1220having a female section 1220 a (e.g. having hollow receptacles, pinholes, or slots) that interfaces with pins 1210 and a male section 1220b (e.g. having pins) that interfaces with the generator or pacemaker.Relatedly, distal leads can be wired to or coupled with a distal sectionof the device and terminate in different pins distinct from the RFwiring of the distal electrodes. An ablation generator or ESU can havean integral pacing function. Alternatively, an adaptor connector can beconfigured identical to a female connection of the ablation generatorfor insertion of the probe cable with positive and negative male pinscompatible with an external pacemaker for subsequent suction appliedpacing following an ablation procedure.

Optionally, systems can be configured to provide a linear array with thesame or a different device in various lengths. By withdrawing the probeinto a housing so that only the distal portion of the electrode isexposed, the same device may be used to achieve bipolar pacing with asuction applicator to ensure tissue contact. FIG. 12A illustrates asurgical system 1200 a that includes an ablation mechanism 1210 a havinga first electrode assembly 1212 a and a second electrode assembly 1214a. In some instances, either or both of the electrode assemblies mayinclude between about 2 and 3 electrodes. System 1200 a also includes asuction stabilizer mechanism 1220 a coupled with or in operativeassociation with the ablation mechanism. Suction stabilizer mechanism1220 a defines a recess 1224 a into which patient tissue can be drawn,for example by creating a vacuum or introducing a relative negativepressure within the recess. Suction stabilizer mechanism 1220 a can havea length within a range from about 4 cm to about 8 cm. In use, system1200 a can provide for the formation of transmural lesions, withoutbending at sharp angles. For example, suction stabilizer mechanism 1220a can maintain suction when bent to a radius of curvature that is lessthan about 3 cm. As shown here, system 1200 a can be at least partiallyhoused within, and configured to translate relative to, a delivery tube1230 a. For example, system 1200 a can be extended outward from the tube(e.g. through and/or away from a distal aperture) as indicated by arrowA, or withdrawn toward the inside of the tube as indicated by arrow B.The exposed electrode sections that extend out of the delivery tube canbe used to deliver ablation treatment to the patient, whereas thecovered electrode sections within the delivery tube are prevented fromcontacting the patient tissue. Hence, use of the delivery tubefacilitates the administration of lesions having a variety of lengths,based on the adjustable length of the exposed electrode sections. Use ofdistal electrode portions or leads can facilitate the application ofbipolar pacing to the patient tissue. The adjustability of the exposedelectrode length in surgical system 1200 a makes this embodiment wellsuited for the application of connecting lesions to patient tissue. Insome cases, distal spot pacing electrodes or pacing electrodeselectrically separated from the ablation electrodes may be used forpacing.

The pacing ability provided by the leads can be used to artificiallypace or stimulate the heart as desired, to evaluate the transmurality ofa lesion. For example, some techniques involve the application of acircular ablation that surrounds the bases of the patient's pulmonaryveins, in an attempt to create a transmural ablation. Pacing electrodesor leads can be placed within the boundaries of this ablation, and astrong pulse can be delivered to a central location via the leads.Resulting cardiac contraction that is confined to tissue located withinthe circular ablation, and that occurs at the same beat or pulse rate asthe delivered pacing stimulus, is indicative of a transmural lesion orconduction block. Alternatively, pacing electrodes can be placed outsidethe boundary of the circular ablation for delivery of a stimulationpulse. If the resulting cardiac contraction is limited to the exteriorof the circular ablation, and does not occur within the inside of theablation boundary, it is possible to conclude that a complete lesion orconduction block is formed.

Pacemaker devices often do not provide a high current drive capability.For example, typical pacemakers may be configured to drive about 10milliamperes. According to embodiments of the present invention, tissuetreatment systems can be configured to deliver about 10 milliamperesduring a tissue pacing or stimulating protocol, and about 1 ampere for atissue heating or ablation protocol. When a delivery tube or sheath ispositioned to a sufficiently distal location along a stabilizermechanism, the surface area of exposed electrodes can be relatively low.Hence, low voltage can be applied via this low surface area as part of apacing procedure. In some instances, 10V and 10 milliamperes can bedelivered for high intensity pacing. A delivery tube or sheath can alsobe retracted, thus exposing a greater surface area of electrodes. Insuch configurations, higher levels of energy can be administered so asto create lesions. For example, about 100 Volt and 1 ampere can bedelivered for ablation. By sliding the delivery tube or sheath along thelength of a stabilizer mechanism, it is possible to adjust the exposedsurface area of electrodes. Similarly, by maneuvering an introducerand/or tubing mechanism as shown in FIG. 11, it is possible to adjustthe positioning of electrodes on the patient tissue. The sheath andstabilizer mechanism shown in FIG. 12A can be constructed of or includematerial such as various elastomeric polymers, such that the sheath andstabilizer mechanism slide easily along one another. For example, thesheath may be constructed of silicone, and the stabilizer pod may beconstructed of polyurethane. In some cases, both components areconstructed of or include a soft durometer polyurethane. It is alsohelpful that the materials used ensure that vacuum administered throughthe suction stabilizer can operate to form and maintain a seal betweenthe sheath and stabilizer pod. Exemplary elastomeric polymers provideelectrical and thermal insulative properties which are helpful incarrying out the methods described herein. Suction or vacuumadministered through a suction stabilizer can operate to reliably attachthe suction stabilizer to both the sheath and the patient tissue. Hence,the sheath can be constructed with the appropriate dimensions andcurvature so that it forms a seal with the stabilizer mechanism, andprovides an interface that approximates tissue during the ablation. Whenthe sheath is advanced toward the distal end of the stabilizer, thetreatment system provides a set of small tip electrodes which pacetissue reliably when energized, because the electrodes are securelyengaged with the tissue as a result of the suction. By providing asheath that can be adjustably positioned relative to the suctionstabilizer, the treatment system can be configured to switch between anablation delivery mode and a pacing delivery mode, during the course ofa single treatment.

Because some surgical systems can be configured to present shorter orlonger exposed ablation element segments, in addition to providing apacing function, such systems may also be well suited for creatingvariable length lesions and connecting lesions, such as those describedin U.S. patent application Ser. No. 12/124,743 and Ser. No. 12/124,766filed May 21, 2008, the contents of which are incorporated herein byreference. By covering a large portion of the electrodes, and leavingexposed a set of small tip electrodes, it is possible to adhere thesesmall tip electrode configurations to the heart and perform a pacingprocedure with them. The distal sections of electrodes can be placed onthe inside of a lesion boundary, or on the outside of a lesion boundary,following formation of the lesion, and can be used to confirm whether apacing stimulus applied by the electrodes paces cardiac tissue on theother side of the lesion. Whereas relatively large voltages andamperages are applied through the electrodes during an ablationprocedure, much lower voltages and amperages are applied through thesame electrodes during the pacing procedure. In some instances, theamount of exposed surface area of electrodes can be about 10 mm² orless.

FIG. 12B shows aspects of a surgical system 1200 b according toembodiments of the present invention. Surgical system 1200 b includes aprobe assembly 1210 b having a stabilizer pod mechanism 1220 b, aribcage mechanism 1230 b, and an electrode assembly 1240 b. Further,surgical system includes a sheath 1250 b and a support mechanism ordistal probe capture mechanism 1260. As shown here, support mechanismincludes two pacing electrodes 1262 b and 1264 b. Hence, embodiments ofthe present invention encompass surgical systems having a probe deliverypush tube sheath and a probe assembly with an internal suction surface.In some instances, systems may also include a distal probe capturemechanism or support mechanism. In some instances, a probe delivery pushtube sheath may include a separate lumen for a retrieval device such asa capture mechanism.

Additional exemplary probe delivery push tube sheath configurationswhich are well suited for use with the surgical systems disclosed hereinare described in US Patent Publication Nos. 2008/0294154 and2009/0048591, the contents of which are incorporated herein by referencefor all purposes. In some cases, a probe delivery push tube sheath mayinclude a soft or hard probe alignment tip.

FIG. 13 depicts aspects of a surgical system 1300 according toembodiments of the present invention. Surgical system 1300 includes ashort probe assembly 1370 having a stabilizer pod mechanism 1345, aribcage mechanism, and an electrode assembly 1325. Further, surgicalsystem includes tubing assembly 1340 coupled with the probe assembly1370 via a U-joint mechanism 1335. Such surgical systems are well suitedfor use in creating connecting and right side lesions. Short probeassembly 1370 has an active electrode set that includes two electrodes1320, 1315 on an active side 1353 of the probe assembly. An indifferentor return electrode is hidden from view on a return side 1355 of theprobe assembly 1370. As shown here, probe assembly 1370 includes adistal section 1302 and a proximal section 1304. Each of the distalsection 1302 and the proximal section 1304 include tissue transitioningress features (i.e. distal ingress feature 1305 and proximal ingressfeature 1306) that allow tissue to move from a relatively flat condition(e.g. outside of the treatment tissue area) to an enfolded condition(e.g. at the treatment tissue area). The distal portion 1302 of probeassembly 1370 includes grab tabs 1360 that can be grasped formaneuvering the probe assembly. The distal portion 1302 of probeassembly 1370 also includes a magnetic housing 1365 having a profilethat allows the housing to be indexed rotationally with an introducer.The suction stabilizer pod mechanism 1345 includes rolled over edges1310 that allow easy tissue ingress and egress into the suction recessand inter-rib webs 1350 that hold the rolled edges down and keep tissueout of spaces between tines of the electrodes 1325. U-joint mechanism1335, which couples a distal section of tubing assembly 1340 with aproximal section 1304 of probe assembly 1370, can operate to helptransmit torque forces, axial forces, suction, and electrical wiresbetween the tubing assembly and probe assembly.

FIG. 13A shows aspects of a probe assembly 1300 a according toembodiments of the present invention. As depicted here, probe assemblyincludes a suction pod mechanism 1310 a, a ribcage mechanism 1320 ahoused by the suction pod mechanism, and an electrode mechanism 1370 a.Such components can be made or constructed from a variety of materials.For example, suction pod mechanism 1310 a may include or be constructedof an elastic material or composition, such as silicone, polyurethane,polycarbonate, another suitable polymer, or combination of polymers orthe like. Ribcage mechanism 1320 a may include or be constructed of aflexible or semi-flexible non-conductive material or composition. Forexample, a ribcage mechanism may include any of a variety of syntheticpolymers, thermoplastic polymers such as polycarbonate, or anothersuitable plastics, either alone or in combination. Electrode mechanism1370 a may include or be constructed of a conductive material orcomposition, such as platinum, platinum iridium, stainless steel, gold,silver-silver chloride, nickel coated copper, or other non-toxic metals.As shown here, probe assembly 1300 a may also include webs 1340 a, whichmay be part of or extensions of suction pod mechanism 1310 a, which arepositioned between intercostal spaces or gaps of the ribcage mechanism,and also in spaces 1330 a between individual tines of the electrodemechanism. For example, webs 1340 a may extend from the suction podmechanism, through gaps in the ribcage mechanism, and protruding out toor flush with the inner surface of the electrodes. Such webs can help tokeep tissue out of spaces between the electrode tines, for example whensuction is administered to the tissue via the probe assembly. Suctionpod assembly 1310 also includes a rolled over edge 1350 a that allowseasy tissue ingress and egress. For example, when suction is applied,tissue can be drawn into a recess 1360 a which is defined by the probeassembly. Conversely, when suction is discontinued, tissue can exit therecess. Hence, embodiments of the present invention encompass surgicalsystems that include a stabilizer or guide mechanism defining an innerrecess 1360 a, and an ablation mechanism disposed within the innerrecess 1360 a of the stabilizer or guide mechanism. The ablationmechanism having a first electrode side 1382 a and a second electrodeside 1384 a opposing the first electrode side. As shown here, electrode1370 a is disposed along second electrode side 1384 a. The ablationmechanism also includes another electrode mechanism (not shown) disposedalong first electrode side 1382 a. The ablation mechanism is to receivea portion of the tissue between the first electrode side 1382 a and thesecond electrode side 1384 a. In some instances, a stabilizer mechanismmay include a pod assembly 1310 a coupled with a ribcage mechanism 1320a. In some instances, an ablation mechanism may include a ribcagemechanism 1320 a coupled with an electrode mechanism (e.g. electrode1370 a). In use, the surgical system or treatment probe assembly can beplaced at or near the tissue of a patient. A vacuum can be deliveredthrough the stabilizer mechanism, for example along a dorsally locatedchannel, lumen, or space 1390 a. The vacuum or suction can betransmitted through intercostal spacings or gaps of the ribcagemechanism and/or electrode, so as to draw a portion of the patienttissue into the ventrally located inner recess 1360 a, and between thefirst electrode side 1382 a and the second electrode side 1384 a. Atreatment procedure, which may include a pacing protocol and/or anablation protocol, can be administered to the tissue via the ablationprobe assembly 1300 a. As depicted here, the probe assembly 1300 a mayalso include a vertebral ridge or protrusions 1395 a, which operate toprevent or inhibit dorsal space 1390 a from collapsing when suction istransmitted therethrough. As shown here, vertebral elements 1395 a maybe present as dorsally extending projections of ribcage mechanism 1320a.

FIG. 14 depicts aspects of a surgical system 1400 according toembodiments of the present invention. Surgical system 1400 includes along probe assembly 1470 having a stabilizer pod mechanism 1435, aribcage mechanism, and an electrode assembly. Further, surgical systemincludes tubing assembly 1430 coupled with the probe assembly 1470 via aU-joint mechanism 1425. Such surgical systems are well suited for use increating full loop lesions. Long probe assembly 1470 has an activeelectrode set that includes seven electrodes (represented by bars 1415)on an active side 1453 of the probe assembly. Long probe assembly 1470also includes an indifferent or return electrode (represented by bar1445) on a return side 1450 of the probe assembly 1470. As shown here,probe assembly 1470 includes a distal section 1402 and a proximalsection 1404. Each of the distal section 1402 and the proximal section1404 include tissue transition ingress features (i.e. distal ingressfeature 1405 and proximal ingress feature 1406) that allow tissue tomove from a relatively flat condition (e.g. outside of the treatmenttissue area) to an enfolded condition (e.g. at the treatment tissuearea). The distal portion 1402 of probe assembly 1470 includes grab tabs1460 that can be grasped for maneuvering the probe assembly. The distalportion 1402 of probe assembly 1470 also includes a magnetic housing1465 having a profile that allows the housing to be indexed rotationallywith an introducer. The suction stabilizer pod mechanism 1435 includesrolled over edges 1410 that allow easy tissue ingress and egress intothe suction recess and inter-rib webs 1440 that hold the rolled edgesdown and keep tissue out of spaces between tines of the electrodes.U-joint mechanism 1425, which couples a distal section of tubingassembly 1430 with a proximal section 1404 of probe assembly 1470, canoperate to help transmit torque forces, axial forces, suction, andelectrical wires between the tubing assembly and probe assembly.According to some embodiments, a probe assembly may include multipleactive electrodes such as electrodes 1415 shown in FIG. 14. In someinstances, a probe assembly may include 6 or more active electrodes, forexample.

With returning reference FIG. 1D, a serpentine ribcage mechanism 120 dcan provide spaces 121 d (e.g. intercostal spacings or gaps) along theserpentine spine between ribs 122 d, and such spaces 121 d between ribs122 d allow for flexibility along the length of the ribcage mechanism.Further, such spaces 121 d between the ribcage ribs (and electrodetines) allow suction pressure to be maintained outside and along thefull length of the inner chamber or recess of the probe assembly, andalso allow this suction as provided by a suction source to betransmitted through the ribcage mechanism so as to communicate directlywith the inner recess. Screened or perforated ceiling members, whichtypically include a nonconductive material such as plastic, can preventor inhibit tissue from going too far into the stabilizer recess, thusinhibiting occlusion of the suction pathway. The maintenance of suctionor vacuum along the entire length of the suction pod or ablation deviceassembly can be ensured using such screening to prevent tissue fromoccluding the suction channel. The effective depth of the channel withinthe suction pod can be determined by the depth at which the screening isplaced within the suction pod structure. The space between the screenand the central backbone body of the suction stabilizer provides anunencumbered channel for the suction to be transmitted all along thelength of the stabilizer or ablation device. Such screen or perforatedceiling members are well suited for use with a variety of surgicaltreatment systems. In some instances, such suction transmission featurescan be accomplished with a serpentine or fishbone ribcage mechanism asdiscussed elsewhere herein.

Treatment devices can be constructed in different lengths andconfiguration. For example, some systems may include a relatively longertreatment device having a flexible probe assembly or pod type suctionstabilizer, and some systems may include a relatively shorter treatmentdevice having a short segment type suction stabilizer. Each of thesedevices can be applied to patient tissue via suction. In some instances,a surgical system may include an ablation mechanism having a firstelectrode assembly and a second electrode assembly, and a suctionstabilizer mechanism coupled with or in operative association with theablation mechanism. In some cases, either or both of the electrodeassemblies can include about five to ten electrodes (see e.g. FIG. 14).Relatedly, some system embodiments may include a probe assembly havingmore than one active, temperature controlled electrode, but less than 6active electrodes (see e.g. FIG. 13).

Individual active electrodes can have a length between about 2 cm andabout 4 cm. As described elsewhere herein, embodiments of the presentinvention encompass systems and methods for administering ablationenergy (e.g. radiofrequency energy) in a temperature controlled manner,such that temperature control can be used to maintain tissue at desiredtemperatures when producing a lesion or lesion set. According to someembodiments, a shorter electrode length may enhance the resolution ofpower delivered to each electrode of an electrode set, with regard totissue variations that may be present along the length of a probeassembly. For example, some tissue may have a covering of fat, or mayhave a variable thickness profile where one section is thicker orthinner than an adjacent section. Similarly, some portions of tissue maybe more affected by rapidly moving blood on the other side of the tissuewall which can act as a more effective heat sink. By providingelectrodes of a shorter length within an electrode set, it is possibleto accurately adjust the power profile or amounts at a locally or finelyresolved level, so as to maintain a desired tissue temperature forlesion creation along a length of the probe assembly. Exemplary probeassemblies may include individual electrical connections and monitoringfor individual electrodes of an electrode set. In some instances, asingle return electrode can be equal or similar in length to acorresponding set of multiple active electrodes. In some instances, areturn electrode may be several times longer than a single activeelectrode from a set of multiple active electrodes. the activeelectrodes. A suction stabilizer pod or mechanism can define a recessinto which patient tissue can be drawn, for example by creating a vacuumor introducing a relative negative pressure within the recess. In someinstances, a system can be wrapped or cinched around a patient tissuestructure, such as the patient's heart or pulmonary veins. By advancinga trocar or tube along a length of the system, or by maneuvering atubing assembly and introducer mechanism (see e.g. FIG. 11), it ispossible to tighten or snug the ablation mechanism and suctionstabilizer mechanism against the patient tissue. Use of a lead line canhelp to keep a distal portion of the suction stabilizer in closeproximity with a more proximal section of the suction stabilizer. Thecircumference or diameter of the belt loop system configuration can beadjusted as desired to accommodate any of a variety of patient tissuesizes and shapes. As with other embodiments described herein, a surgicalsystem can be used to produce linear lesions or encircling lesionsaround tissue structures such as one or more pulmonary veins, forexample by wrapping or cinching the device about the patient's heart inthe appropriate position. Hence, surgical systems may include a cinchingmechanism to allow the circumference of the ablation mechanism to beadjustable to the tissue structure being ablated. A cinching mechanismmay be facilitated by fixing the distal end of the suction stabilizer orbelt and retracting the proximal end or by a separate mechanism thatcinches both the distal and proximal sections of the suction stabilizer.Exemplary cinching and loop locking mechanisms and related techniqueswhich are well suited for use with embodiments of the present inventioncan be found in US Patent Publication Nos. 2008/0294154 and2009/0048591, the contents of which are incorporated herein by referencefor all purposes. In some instances, a suction stabilizer mechanism issufficiently flexible to achieve a small radius of curvature forwrapping about or interfacing with acute tissue surfaces. For example,the suction stabilizer mechanism can be configured to maintain suctiononto the tissue when subjected to a bend having a radius of curvature of1 cm or larger. In some cases, a suction stabilizer mechanism has apreformed shape or bend. In some cases, a suction stabilizer mechanismhas no preformed shape or bend.

With returning reference to FIG. 11A, portions of ablation assembly 1100a having a small radius of curvature and/or which are out of plane withadjacent portions of the ablation assembly can be translated along thelength of the probe assembly so that the probe assembly can hug orconform with irregular and out-of-plane curves of a tissue path, even asthe probe assembly is advanced along the path as indicated by arrow A.In some instances, the ablation assembly may be advanced along acircular path. In some instances, the ablation assembly may be advancedalong a non-circular path. Accordingly, embodiments of the presentinvention provide probe assemblies that are configured to conform to anyof a variety of non-uniform or irregular tissue geometries or surfaces.

With returning reference to FIG. 11, in some instances, a stabilizermechanism can have a length within a range from about 15 cm to about 30cm, and can be configured to create a box lesion completely around ornearly completely around all four pulmonary veins (PV) while maintainingcontact along that entire length. Hence, a stabilizer mechanism can flexand adhere via suction to a long section of tissue. In some instances, astabilizer mechanism is configured to bend at a minimum radius ofcurvature of about 1.5 cm or 0.5 inches as it approaches or approximatesthe based of the left pulmonary veins during a surgical treatment. Thestabilizer mechanism may also rotate at various angles about alongitudinal axis. Optionally, the stabilizer mechanism can beintroduced through the right side of a patient, wrapped or guided aroundthe based of the left superior pulmonary veins on the left atrium nearthe left atrial appendage, and positioned around the left atrium,encircling the inferior pulmonary veins, changing its angulation androtation in a non-planar path. As described elsewhere herein, a probeassembly can be provided in a non-adjustable length sufficient to createa full box lesion on a patient tissue. Relatedly, a probe assembly canbe provided with a cinching mechanism that operates to adjust the lengthof an exposed portion of an electrode assembly, and such probeassemblies can be used to form a full box lesion on a patient tissue aswell.

Suction stabilizer or pod mechanisms having various geometricconfigurations can be incorporated in certain system and methodembodiments of the invention. In some instances, a suction stabilizermechanism can include a first slot or lumen that houses wiring whichconnects a first ablation mechanism with an ESU, and a second slot orlumen that houses wiring which connects a second ablation mechanism withthe ESU. In some embodiments, such as those which may be exemplified byFIG. 9, some or all of the ablation mechanism wiring (which provideselectrical connectivity between an ESU and electrodes 912, 914, iscontained in a suction space 950 on both right and left sides, sharingthe space with the suction function. In some instances, the wiring slotor lumen can be potted after the wiring is in place. Optionally,steerable cable members can be housed within the slots or lumens.

Exemplary embodiments provide surgical systems having an ablationmechanism with a first electrode assembly and a second electrodeassembly, and a suction stabilizer mechanism coupled with or inoperative association with the ablation mechanism. In some instances,treatment systems can include or operate in association with a clampingmechanism (see, e.g. FIG. 17), which can be configured to track along asuction stabilizer mechanism and promote tissue compression. Forexample, a suction stabilizer mechanism may include a first side railand a second side rail, and a clamping instrument can operate to engageone or both of the side rails. The clamping instrument, in combinationwith the side rails, can help to maintain contact between the stabilizermechanism and the patient tissue. In some cases, a roller device can beused to enhance the interface between the stabilizer and patient tissue.A clamping mechanism can operate to urge the first side rail toward asecond side rail, or to urge second side rail toward first side rail, orboth. In some instances, the side rails and the clamping instrument canbe used to clamp a linear section of tissue between the electrodes.

In some instances, a suction stabilizer mechanism may include a firstside rail and a second side rail, and the clamping instrument canoperate to engage one or both of the side rails. Electrode assemblies ofthe system can present an angled or wedged configuration, such thatopposing faces of the electrodes define an angle or wedge. In someinstances, opposing faces of two electrodes can present a parallel orsubstantially parallel alignment configuration. When a system is in aclamped configuration, tissue can be maintained in place by both vacuumand the clamping force. In this way, the side rails and the clampinginstrument can be used to clamp a linear section of tissue between theelectrodes.

According to some embodiments, a bipolar epicardial transmural ablationsystem, can be placed on the patient tissue, and the electrodes may forma seal around the pod. Suction can be applied, thereby attaching orapproximating tissue with the ceiling of the pod and raising theendo-surface. As control rods are squeezed together, control arms liftthe pod and tissue to appose inner tissue surface. The system mayprovide current flow between electrodes across folded tissue. Anexemplary system may include a suction pod, two control arms, twocontrol rods, an electrode pair and associated wiring, a suction podlift point, suction inlets on the inside of the pod and optionally atthe end of the pod, and posts or ribs on the ceiling of the suction podto help maintain suction on tissue in a manner similar to that describedwith regard to the screen ceiling. Handles can be used to actuate thecontrol rods and arms, in a parallel-action manner. The lower margins ofthe suction pod can be squeezed together to fold the tissue while thesuction pod lifts and holds the tissue between the sides of the pod. Thetwo rods along the side of the system present a structure similar tothat of a bicycle chain with the axis of the links running across, sideto side, that allow a curve to be formed while maintaining lateralstability. The system can be configured as a short connecting lesiondevice or as a long loop device as described elsewhere herein. Further,the system can accommodate differing thicknesses of tissue.

According to some embodiments, a treatment system may include a bipolarablation suction pod with a flexible spine for curved surfaces. Forexample, a system can present a concentric tube construction that can beactuated to help approximate the electrodes with patient tissue. Thelower margins of the suction pod can be squeezed together to fold thetissue while the suction pod lifts and holds the tissue between thesides of the pod. The system can be configured as a short connectinglesion device or as a long loop device as described elsewhere herein.The system can accommodate differing thicknesses of tissue, and further,can accommodate different thickness of tissue in the same bite orclamping step where tissue thickness changes along the length of thesystem.

FIG. 15 shows a cross-section view of a probe assembly 1510 of asurgical system 1500 according to embodiments of the present invention.As depicted here, probe assembly 1510 includes a stabilizer mechanism1520, an ablation mechanism 1530 having a ribcage mechanism 1540 coupledwith a first electrode assembly 1550 (e.g. active) and a secondelectrode assembly 1560 (e.g. return). The stabilizer mechanism 1520 canbe constructed of or include a soft elastic material or membrane. Theribcage mechanism 1540 can provide a stiffer structural element forsupporting the electrode assemblies 1550, 1560 and for preventingcollapse of the stabilizer mechanism 1520 during use, such as whensuction is applied so as to draw tissue into or toward a recess 1522defined by the stabilizer mechanism. In many instances, electrodemechanism 1550, 1560 may also contribute to the structural supportprovided by the ribcage mechanism, such that the combined presence ofthe ribcage mechanism and one or more electrode mechanisms inhibit orprevent collapse of the stabilizer mechanism 1520 during use, such aswhen suction is applied so as to draw tissue into or toward a recess1522 defined by the stabilizer mechanism. Electrode assemblies 1550,1560 can be spaced apart from each other by a distance D, which may bewithin a range from about 4 mm to about 6 mm. In some instances,distance D is within a range from about 2 mm to about 10 mm. In someinstances, distance D is about 6 mm. As depicted here, tissue having afirst portion thickness T1 and a second portion thickness T2 can bedrawn into the recess 1522. In some instances, T1 and T2 may each beabout 2 mm. In many cases, T1 and T2 are about the same thickness. Insome cases, T1 may have a different thickness than T2. For example,where cardiac tissue presents one or more trabeculae, or where there areother rapid local tissue thickness changes, T1 and T2 may differ up to50% or more. Atrial tissue thickness can range from about 1 mm to about12 mm, or more where greater amounts of fat tissue are present.Myocardial tissue thickness can range from about 2 mm to about 5 mm, ormore where greater amounts of fat tissue are present. Surgical systemand method embodiments of the present invention are well suited for usein treating such tissues. In some embodiments, surgical system 1500 canprovide a parallel sided bipolar configuration, for clamping a 2 mmportion or thickness of tissue. In some instances, embodiments encompassprobe assemblies having an electrode distance spacing profile thatvaries along the length of the probe assembly. Hence, the width at adistal portion of the probe assembly internal recess may be greater thanor less than an adjacent proximal portion. Probe assemblies that providea variable distance D along the length of the probe assembly can, forexample, accommodate and draw in thicker tissue at the distal end andthinner tissue at the proximal end, or vice versa. Such probe assembliescan be used to treat certain tissue structures such as Waterston'sgroove area, the left superior pulmonary vein (LSPV) or ligament ofMarshall area, or other tissue structures presenting variable thicknessprofiles, and the like. In some instances, probe assembly 1510 can beconfigured for delivery though a 12 mm port, for example. Although theelectrode assemblies 1550, 1560 shown here are parallel or substantiallyparallel to one another, embodiments of the present invention encompassconfigurations where electrode assemblies 1550, 1560 are offset from oneanother at an angle A1 or A2, such as shown in the cross-section view ofFIG. 15A. In some cases, angles A1 and A2 are within a range from about5 degrees to about 30 degrees. In some instances, each of angles A1 andA2 are about 20 degrees. In some instances, angles A1 and A2 are thesame. In some instances, angles A1 and A2 are different. In someinstances, electrode mechanisms 1550 and 1560 are angled so as toprovide a distance D between the electrodes at a lower ventral portionof about 5 mm and a distance D between the electrodes at an upper dorsalportion of about 4 mm. In some cases, electrodes 1550, 1560 can beoffset from one another by an angle of between about 2 degrees and about30 degrees. In some cases, the offset may be about 12 degrees. Someembodiments provide electrode mechanisms that change the angle or thatprovide variable angle profiles along a length of the probe assembly.FIGS. 6A, B, and C for example, show other electrode angle embodiments.Electrodes may present flat tissue-contacting surfaces in some cases, orcurved or contoured tissue-contacting surfaces in other embodiments. Asdepicted in FIG. 15, the probe assembly can be configured or employed sothat when applied to a patient tissue, a gap or open trough 1570 isformed between the opposing tissue portions 1580, 1590. Hence, thegeometry of and/or the positioning of the probe assembly 1510 can beused to create a valley 1570 on the endocardial side of a cardiac tissueso that the blood can flow or circulate through the valley 1570 during alesion creation procedure, particularly when the tissue is relativelythin. In this way, it is possible to inhibit or prevent clot formationduring the surgical procedure. Where the patient tissue has a mediumthickness, the endocardial surfaces of tissue portions 1580, 1590 mayappose each other, and by virtue of the blood being squeezed out due tothe apposition, it is possible to inhibit or prevent clot formation.With thicker tissue, the endocardial surface may only form a shallowgroove, as depicted in FIG. 15B, again allowing the blood to wash thearea of the lesion, thus inhibiting or preventing clot formation. Thecardiac tissue in FIG. 15B may have a thickness of, for example, about 3mm. As shown here, the endocardial surface may appose itself, forexample within the recess of the stabilizer mechanism, and current canflow across the apposed tissue.

As seen in the cross-section view of FIG. 16, a probe assembly 1600 canbe flexed toward the suction recess side 1630 such that the probe formsa curved shape. A neutral plane is follows the curve of the probe andlies upon the area of the probe which is neither stretching norshortening in length. During use, it may be desirable that certaincomponents, such as wires which are connected to the electrodes, not beunduly stretched during flexion. Appropriate positioning of the path ofthese wires along the length of the probe can help to avoid suchstretching. As shown here, the path of the wires 1620 may lie very closeto the neutral bending plane, and therefore the wires experience littlestress or tension during operation. Additionally, from a top view of theprobe, the wires may be installed in a serpentine pattern thataccommodates the small length change due to the offset from the neutralbending plane. Likewise, the wire path through the U-joints may crossnear the pivot points for the same purpose. Typically, a probe assemblyincludes a vacuum space or lumen which houses wires for deliveringelectricity to or returning electricity from the electrodes. Typically,the surgical system is configured so that there is sufficient slack inthe wires, such that the wires do not become taut or strained duringoperation of the system, which may include flexing and twisting of theprobe assembly or other components.

As further depicted in FIG. 16, current can be dispersed from epicardiumto endocardium in a bipolar mode (arrows 1630) as well as in a monopolarmode (arrows 1640). In some cases, for example when treating a tissue ofgreater thickness, the monopolar mode (arrows 1640) may disperse anamount of current that is greater than an amount of current which isdispersed with the bipolar mode (arrows 1630). As shown here, theapposed tissue forms a valley or shallow trough 1650, which can bewashed away by flowing or circulating blood, so as to inhibit or preventclot formation. During operation in the monopolar mode, a ground pad istypically used. For example, a ground pad may be placed against thepatient's back. As shown here, when in the bipolar mode, current isdirected from one electrode (e.g. 1670) to an opposing electrode (e.g.1680). Hence, the current path 1630 locally constrained. In contrast,when in the monopolar mode, current path 1640 is more diffuse orradiating, as the return pad is at a greater distance from the activeelectrode mechanism and there is less local constraint on the currentspread.

FIG. 17 shows a cross-section view of a probe assembly 1700 thatincludes a stabilizer mechanism 1720, and an ablation mechanism having aribcage mechanism 1710 coupled with a first and second electrodeassemblies 1730. As discussed elsewhere herein, and as depicted here,ribcage assembly 1710 can operate to support the suction pod 1720externally against suction forces, and the electrodes 1730 internally.Hence, ribcage mechanism 1710 can support the suction pod 1720 so as toprevent collapsing from suction forces which are generated within theprobe recess 1740. Further, ribcage mechanism 1710 can supportelectrodes 1730 internally in a desired position to enhance contactbetween the electrodes 1730 and the patient tissue which is drawn intothe recess 1740. In some instances, pod or stabilizer mechanism 1720 isconstructed of or includes a thin flexible skin. In this way, theribcage mechanism 1710 may operate to provide an inner skeleton whichgives shape to the stabilizer mechanism 1720 and also absorb and flex inresponse to external forces which may impinge upon the probe assembly,while also remaining sufficiently flexible to allow the stabilizermechanism to remain in a sealed vacuum contact (e.g. via flexible skirtsections 1750) with the tissue, and to provide and enhance contactbetween the electrodes 1740 and patient tissue which is drawn intorecess 1740. The ribcage mechanism 1710 can be configured so that thepocket or channel 1740 is maintained during use, and suction cantherefore travel the full length of the probe assembly. As shown here,suction or relative negative pressure can be administered through anupper or rear channel or lumen 1760, within the probe assembly, andthereafter pass through ribcage mechanism 1710 and electrode 1730 asindicated by arrow A, or pass through ribcage mechanism 1710 asindicated by arrow B. In some cases, pod mechanism 1720 includes podwalls having a first thickness T1, and a skirt section having a secondthickness T2. In some cases, the skirt thickness is less than the wallthickness. The skirt section 1750 at the margins of the pod mechanism1720 can operate to help form and maintain a seal between the probeassembly and the patient tissue, thus allowing the delivered suction todraw the tissue into the recess 1740. The skirt section 1750 may providea thin tapering section that is sufficiently flexible to conform to anysmall irregularities of the tissue surface on a smaller scale.Additional aspects of exemplary skirt features are shown in FIG. 19. Insome instances, surgical systems may include means or clampingmechanisms for squeezing and/or expanding the recess provided by theprobe assembly. For example, systems may include a set of rails or tongs1782, 1784 that can be moved toward each other to reduce the recess orto compress tissue within the recess, and/or that can be moved away fromeach other to expand the recess. Such squeezing means or expanding meansmay include spring-loaded arms or tongs, clamps, rails, and the like. Insome cases, the tongs or clamps can be individually controlled.

In exemplary embodiments, a probe assembly 1800 can be configured to beflexible in an upward direction, a downward direction (as shown here,flexing toward the suction or ventral side), a sideways left direction,a sideways right direction, and in torsion. For any given deflection inthe probe assembly 1800, there can be a related neutral plane 1810,which is bent or curved in correspondence with the deflection.Accordingly, a first portion 1802 of the probe assembly may be intension and a second opposing portion 1804 of the probe assembly may bein compression. The neutral plane 1810 can also be described as theplane where probe assembly material to the outside of that curved planeis in tension and being stretched, and probe assembly material insidethat curved plane is in compression or being shortened in length. Theposition of this neutral plane is determined by the sum of the forceswithin the probe assembly during deflection. When subjected to bendingforces as depicted here, the compressive and tensile forces develop,with higher compressive stresses forming at the ventral portion 1804 ofthe probe assembly and higher tensile stresses forming at the dorsalportion 1802 of the probe assembly. At the neutral plane there is nobending stress. In some embodiments it is desirable to prevent orinhibit stretching of certain probe assembly components during flexionof the probe assembly. For example, it may be an objective to notstretch wires with relatively delicate connections to electrodes, andthus such wires can be positioned along a path 1820 that coincides withthe neutral plane or axis 1810. As depicted here, the path of the wires1820 lies very close to the neutral plane 1810 and therefore experienceslittle stress when the probe assembly flexes. Relatedly, a more proximalsection of the path of wires 1840 may pass through the U-joints neartheir pivot points to minimize electrical wire stretch. Hence, with thewiring path at or near the neutral plane (e.g. slightly dorsal thereto),and at or near pivot points of the U-joint or coupling mechanism, wiresmay experience little or no tension when the probe assembly bends (e.g.in a downward direction) or is otherwise maneuvered during operation.Additionally, from a top view of the probe (see e.g. FIG. 18A), thewires may be installed in a serpentine pattern that accommodates thesmall length change due to the offset from the neutral bending plane. Asshown in FIG. 18A, wiring 1800 a for delivering energy to electrodes ofa probe assembly can be positioned in a zigzag or serpentine pattern.The wiring path may be at or near a neutral plane of the probe assembly.Such wiring configurations can allow a certain amount of slack to bepresent in the wiring, and to remain when the probe assembly is bent(e.g. downward toward the suction side 1830 as shown in FIG. 18). Thewires can be for providing electrical connectivity with active andreturn electrodes, thermocouples, pacing electrodes, and the like. Insome instances, a probe assembly may include an internal tension memberor wire that it positioned at or near the neutral plane 1810. Such aninternal tension member 1850 can be used to transmit pulling forces tothe end of the probe assembly without affecting the probe assemblyitself In some cases, a ribcage mechanism may or may not have theability to resist or transmit tension forces. Such an internal tensionmember can be used as a means to resist or transmit tension through aribcage mechanism, or to increase the ability of a ribcage mechanism toresist or transmit tension therethrough. In some instances, an internaltension member may lie along and contribute to the position of theneutral plane.

FIG. 19 shows a perspective view a probe assembly 1900 according toembodiments of the present invention. As depicted here, probe assembly1900 includes a stabilizer mechanism 1910 having a port 1912 which canreceive suction from a vacuum source via a tubing assembly (not shown).Probe assembly 1900 also includes an ablation mechanism 1920 having aribcage mechanism 1930 coupled with a first electrode assembly 1940(e.g. active) and a second electrode assembly 1950 (e.g. return). Thestabilizer mechanism 1910 can provide an outer stabilizing membrane ormechanism. In some cases, ribcage mechanism 1930 includes a series ofribs which support both the stabilizer mechanism 1910 and the electrodes1950, 1960. As shown here, electrodes can be provided in a serpentineconfiguration. The probe assembly 1900 may also include a skirt orcontinuous raised lip or sealing edge 1960, optionally as part of thestabilizer mechanism 1910, which accommodates irregular surface featuresof the tissue and helps to ensure sealed contact between the probeassembly 1900 and the tissue. A skirt section 1960 at the margins of thepod mechanism 1910 can operate to help form and maintain a seal betweenthe probe assembly and the patient tissue, thus allowing the deliveredsuction to draw the tissue into a recess 1970. The skirt section 1960may provide a thin tapering section that is sufficiently flexible toconform to any small irregularities of the tissue surface on a smallerscale.

FIG. 20 depicts an exemplary electrode mechanism 2000 for use in a probeassembly according to embodiments of the present invention. As shownhere, this electrode mechanism can be used as a monopolar electrode fordelivering a monopolar ablation to a patient tissue. The electrodemechanism can be housed at least partially within a suction podassembly, and may define a recess 2010 into which tissue may be drawnthrough the application of suction as described elsewhere herein. Hence,some probe assembly embodiments may include a monopolar probe electrode2000 that can be used to provide suction, through intercostal spacingsor gaps 2020 between individual tines or ribs 2030 of the electrode, tothe tissue. In this way, suction can be transmitted through the spacesbetween the electrode tines or ribs, as the probe assembly draws tissueinto contact with the electrode, and/or between a first electrode side2040 and a second electrode side 2050 of the ablation or electrodemechanism. In some instances, it may be desirable to control the amountof tissue being drawn into an electrode recess, a ribcage recess, and/ora suction pod recess. In some cases, it is possible to control theamount of tissue being drawn into an electrode recess, a ribcage recess,and/or a suction pod recess by providing a spacing of electrode tabs onribs as well as suction pod webs filling in the gaps between ribs. Insome instances, electrode mechanisms can provide intercostal spacing orgaps 2020 having a width within a range from about 0.2 mm to about 0.5mm. The spacing between electrode tabs or plates can be configured sothat excessive tissue does not bulge or extend into the spacings duringuse, which may act to interfere with suction as it is applied to thetissue. In some cases, such spacing keeps tissue out but allows suctionand movement (which changes the spacing dynamically).

FIG. 21 illustrates aspects of a treatment system 2100 that includes anintroducer assembly 2110 and a probe assembly 2120 according toembodiments of the present invention. As shown here, probe assembly 2120includes a distal section 2130 which houses a magnet 2140. In acorresponding manner, introducer assembly 2110 includes a distal section2180 having a magnetic terminal 2160. Distal sections 2130, 2180 may beconfigured to interface in a male/female connection. For example, asshown here, distal section 2130 provides a female interface that isadapted to receive a male interface provided by distal section 2180. Insome instances, introducer assembly 2110 includes an elongate flexibleshaft 2112, or is otherwise flexible. Introducer assembly 2110 may alsoinclude a rotational or pivoting coupling assembly 2114 that couplesdistal section 2180 with shaft 2112. As shown here, coupling assembly2114 may include a U-joint mechanism. In some instances, a couplingassembly 2114 may include a single U-joint mechanism, a double U-jointmechanism, a triple U-joint mechanism, or a multi-U-joint mechanism.Such coupling assemblies can allow a desired amount of angulation of themagnetic terminal 2160. In some instances, magnetic terminal 2160 mayinclude a magnet 2150, for example which may reside within the terminal2160. In some instances, magnets 2140 and 2150 may have opposingpolarities. Magnetic terminal 2160 may be configured to connectivelymate with distal terminal 2130 of probe assembly 2120.

FIG. 22 depicts aspects of a treatment system 2200 that includes anintroducer assembly 2210 and a probe assembly 2220 according toembodiments of the present invention. As shown here, probe assembly 2220includes a ribcage mechanism 2224, and a distal section 2230 whichhouses a magnet 2240. In a corresponding manner, introducer assembly2210 includes a distal section 2280 having a magnetic terminal 2260.Distal sections 2230, 2280 may be configured to interface in amale/female connection. For example, as shown here, distal section 2230provides a female interface that is adapted to receive a male interfaceprovided by distal section 2280. In some instances, introducer assembly2210 includes an elongate flexible shaft, or is otherwise flexible.Introducer assembly 2210 may also include a rotational or pivotingcoupling assembly that couples distal section 2280 with a shaft. In someinstances, magnetic terminal 2260 may include a magnet 2250, for examplewhich may reside within the terminal 2260. In some instances, magnets2240 and 2250 may have opposing polarities. Magnetic terminal 2260 maybe configured to connectively mate with distal terminal 2230 of probeassembly 2220. As illustrated in the longitudinal cross-section viewshown here, probe assembly magnet 2240 may be a solid magnet within afemale housing element, and introducer assembly magnet 2250 may be ahollow magnet within a male housing element.

FIG. 23 depicts a surgical system 2300 according to embodiments of thepresent invention. As shown here, surgical system 2300 includes anintroducer assembly 2310 and a probe assembly 2320. As shown here, probeassembly 2320 includes one or more electrodes (not shown) and a ribcagemechanism that reside within a flexible suction pod mechanism (notshown). Probe assembly 2320 may also include a distal section 2330 whichhouses a magnet 2340. In a corresponding manner, introducer assembly2310 includes a distal section 2380 having a magnetic terminal 2360.Distal sections 2330, 2280 may be configured to interface in amale/female connection. For example, as shown here, distal section 2330provides a female interface that is adapted to receive a male interfaceprovided by distal section 2380. In some instances, introducer assembly2310 includes an elongate flexible shaft, or is otherwise flexible.Introducer assembly 2310 may also include a rotational or pivotingcoupling assembly that couples distal section 2380 with a shaft. In someinstances, magnetic terminal 2360 may include a magnet 2350, for examplewhich may reside within the terminal 2360. In some instances, magnets2340 and 2350 may have opposing polarities. Magnetic terminal 2360 maybe configured to connectively mate with distal terminal 2330 of probeassembly 2320. In some instances, distal section 2380 presents a malemating feature having an ovalized or non-circular cross-section, andlikewise, distal section 2330 presents a female mating feature having acorresponding ovalized or non-circular cross-section. For example,distal sections 2330, 2380 may present corresponding oval shapes, whichallow an indexed coupling of the probe assembly 2320 with the introducerassembly 2310 such that when the probe assembly 2320 and the introducerassembly 2310 are magnetically engaged, the operator is able to applytorque, tension, and/or compression from the introducer assembly 2310 tothe probe assembly 2330 (e.g. via a U-joint of the introducer assembly).Hence, for example when a U-joint 2370 is bent off axis, the operator isadditionally able to apply a bending force to the probe assembly inorder to generate a curve.

FIG. 24 depicts aspects of a surgical system 2400 according toembodiments of the present invention. As shown here, system 2400includes an introducer assembly 2410 having a flexible tubing or shaftmechanism 2412. The flexible tubing or shaft mechanism 2412 may alsocorrespond to the flexible tubing or shaft mechanism 2312 shown in FIG.23, or the flexible tubing or shaft mechanism 2212 shown in FIG. 22, orthe flexible tubing or shaft mechanism 2212 shown in FIG. 21, forexample. In FIGS. 12-23, a distal section of the flexible tubing orshaft mechanism is shown, whereas in FIG. 24, a proximal section of theflexible tubing or shaft mechanism is shown. As depicted in FIG. 24,surgical system 2400 may also include a stylet mechanism 2405. Asdepicted here, stylet mechanism 2405 may include a handle 2420, amagnetic housing portion 2430, and a malleable wire shaft 2440.Introducer assembly 2410 may include a magnetic U-joint mechanism 2414similar to a U-joint located at a proximal section of the assembly 2410.In some instances, introducer assembly 2410 may include a magneticterminal 2450 at the proximal section of the assembly 2410. In someinstances, the introducer assembly may include a hollow magnet in a softhousing, with or without a U-joint mechanism at the proximal section. Insome cases, for example where the introducer does not include a U-jointat the proximal section, a soft housing may have one or more radialholes in the side of the housing behind the magnet that lead into thelumen of the hollow introducer tubing. The stylet mechanism 2405 may beused, for example, when magnetically disconnecting the introducerassembly 2410 from the distal end of a probe assembly, which may be outof easy reach in the anatomy. In some instances, stylet mechanism 2405can be slidably coupled with introducer assembly 2410. For example, amalleable wire shaft or element 2440 of stylet mechanism 2405 may beintroduced into a proximal section of flexible tubing 2412.

Any of the coupling mechanisms or configurations for coupling a probeassembly with an introducer assembly as disclosed herein may also beused for coupling a stylet mechanism with an introducer assembly. Insome instances, the stylet shaft 2440 can be inserted either throughU-joint mechanism 2414, a hollow magnetic U-joint, a hollow magnet in asoft housing, or into one of the holes in the side of the soft housing,and down the length of the introducer lumen or flexible tubing 2412 tothe distal end thereof end. In some instances, the stylet mechanism maypass into a hollow magnet at the distal end of the introducer assembly,and when the stylet handle 2420 is pushed into full engagement with theproximal section of the introducer assembly 2410, a distal section ofthe elongate shaft 2440 can contact the distal section of the probeassembly (e.g. the probe assembly magnet), and thus operate to separatea probe assembly distal section magnet and an introducer assembly distalsection magnet away from each other. In this way, once the introducerassembly has been used to place the probe assembly where desired, it ispossible to disengage the probe assembly from the introducer assembly,and hence the introducer assembly can be withdrawn from the treatmentsite, while allowing the probe assembly to remain at the treatment site.

In some instances, the stylet mechanism 2405 may operate to stiffen theintroducer assembly, for example, when the elongate shaft 2440 is placedwithin the tubing assembly 2412. Such a stiffening technique can beemployed when inserting the introducer assembly into the patientanatomic pathway or when maneuvering the introducer assembly within thepatient anatomy. In some instances, the introducer assembly can beplaced within the patient body, with the distal section of theintroducer extending to an easily accessible location (e.g. outside ofthe body). The distal section of the introducer assembly can then becoupled with a distal section of the probe assembly, and the introducerassembly can then be retracted, thus drawing the probe assembly into thepatient anatomy, as the probe assembly follows the path of introducerassembly. In other words, once the introducer assembly is in place, itcan be magnetically coupled to the probe assembly outside the body, andthe introducer assembly can be used to lead the probe assembly by themagnetic connection into a position in the anatomy, pulling the probeassembly around anatomical curves or structures, as needed throughtension applied to the introducer assembly. In some instances, anintroducer assembly may not reach completely around the target anatomyat first placement, so a second similar flexible introducer assemblywith or without a stylet mechanism inserted therein may be introduced inthe opposite direction along the anatomic pathway until the magneticends of both introducers meet making a long complete loop in, around andout of the patient to so that tension may be applied to one end andcompression applied to the other to advance the probe into position.This second introducer assembly may be removed from its magneticconnection to the first introducer assembly by hand outside the body andthe stylet mechanism may be used as elsewhere described herein whendesired to remove the introducer assembly from the probe assembly.

Relatedly, a positioner instrument assembly having a magneticallyattractive element or ball on a malleable or stiff shaft with a handlemay be used to retrieve the end of the probe introducer assembly whenthe introducer assembly is deep in the anatomy and/or used on themagnetic distal end of the probe assembly itself as a positionerinstrument to manipulate the probe assembly at a close distance. Such apositioner instrument may have an axial push button on the handle thattranslates a long, thin rod that runs the length of the positionerinstrument in order to extend the rod out of a hole in the magneticallyattractive element or ball end to eject or disconnect the magnet fromthe attached device. Where such a positioner instrument has a malleableshaft, the rod may also be flexible, for example, made of material suchas a plastic. Similarly, a positioner instrument having a handle withpush button, a stiff shaft, and a magnetic U-joint with hollow magnetfor a flexible rod to pass therethrough may be used for similarpurposes.

Hence, embodiments of the present invention encompass a variety ofcoupling means, such as magnetic coupling mechanisms, which can be usedto transmit torque between an introducer assembly and a probe assembly.

FIG. 25 depicts an exemplary probe assembly 2500 extending from a portdevice or sheath 2510. The port device 2510 shown here has a 12 mmdiameter, although other size configurations may be used.

In some instances, a suction pod of the probe assembly may includegraphics or markings thereon, for example, in the form of singlelengthwise stripes along both sides that indicate where active andreturn electrodes are located. On some embodiments (e.g. long probeassembly), graphics or markings bearing the color green, which shows upwell in a surgical environment, may be used indicate the returnelectrode side. Embodiments also encompass suction mod mechanisms havinggraphics or markings on the side of the pod assembly which is intendedto be placed upward during a typical cardiac surgery. The color black,which also shows well in surgery, may be used for graphics or markingson the opposite side. In some cases, graphics or markings may includestripes that are interrupted by short breaks to indicate the breakbetween electrodes. The stripes themselves can indicate the placement ofthe electrodes and their start and finish lengthwise. Down thecenterline of the probe assembly on the back side there may be numbersindicating the electrode number inside of the probe assembly, which canbe used to aid in determining which electrode is over what anatomicstructure and therefore which electrode is to be turned on or off. Othernumbering, lettering, and marking schemes may be employed for surgeonfeedback. Similarly, an introducer assembly may have lengthwise markingsthat correspond to those on a probe assembly such that moving theintroducer assembly one marking segment causes corresponding movement ofprobe assembly which may be out of sight.

Additional Aspects of Ablation Devices and Methods

In some instances, an end plug or cap is attached with the distal end ofthe jawbone at the tip of the jaw. Exemplary jawbone mechanisms andrelated systems are described for example in U.S. Patent Publication No.2011/0152860, the contents of which are incorporated herein byreference. The end plug can be at least partially placed within theinside of the boot. In operation, the jawbone and end plug rotatetogether relative to the boot which remains stationary. The end plug maypresent a hard point or surface where a surgeon or operator can placetheir finger when rotating the jaw to a new position.

During a surgical procedure, the surgeon may slide the clamp devicewithin the patient and underneath the pulmonary veins or otheranatomical feature. In some instances, the surgeon may wish to advancethe jaws along a particular path. The surgeon may maneuver the clampdevice alone, without assistance from a supplemental device or guide. Insome instances, a surgeon may thread a piece of rubber, tubing, surgicaltape, or other soft and flexible material along a particular insertionpath, for example by using their fingers or another clamp. The threadingelement can be attached with the ablation clamp device, for example at adistal section of the end plug or boot, and the threading element can beused to help navigate the ablation clamp device throughout the patientanatomy.

In some instances, the threading element is fed along the desirednavigation path, and then a proximal section of the threading element isattached with the ablation clamp, for example at a distal section of thelower jaw clamp. For example, a rubber tubing can be slipped over thedistal tip of the lower jaw clamp. The operator or physician may thenpull on or use a distal section of the threading element to help drawthe ablation clamp as desired within the patient anatomy. Suchtechniques may be useful to avoid having a distal end of the jaw clampinadvertently punch through or lacerate the patient tissue. Once theclamp jaw is positioned as desired, the threading element can be severedor removed from the jaw clamp.

In some instances, the end plug may have a holes or holes that accept athreading element such as a long suture. The surgeon may place thesuture at the end of the jaw tip, and through the hole, so as to attachthe long suture with the jaw tip or end plug. The surgeon may also takea piece of rubber tubing which commonly used in operating room, andplaced an open end of the tubing next to the suture. The tubing can beelastic, flexible, and soft, and suitable for use within the patienttissue anatomy. In some cases, the tubing has a lubricious quality whenwet. The surgeon may then take a wire, which may be folded in half,insert the wire through one end of the tubing and out the other, and usethe wire (e.g. a looped end) extending from the other side to snag thesuture. The wire can then be withdrawn back into the tubing, thusdrawing the suture into the tubing. The tubing can then be snuggedagainst the jaw tip or end plug, for example by pulling on the sutureaway from the clamp and pushing on the tubing toward the clamp. Thesnagging wire may be discarded. The tubing can help to insulate thesuture from contacting or pressing against patient tissue such as anartery. While holding the distal end of the suture and the distal end ofthe rubber tubing, the surgeon may couple the suture with the rubbertubing, so that the interior suture provides a tension member within therubber tubing. For example, the surgeon may apply a hemostat or clampacross the tubing, so as to pinch the tubing against the suture. Thisclamping can operate to lock the tension member or suture within thecompression member or tubing, so that the tension member and thecompression member become a unit. The surgeon can then pull on thedistal end of the tubing, without having the tubing come off of thedistal end of the clamp jaw. In a sense, the tension member andcompression member become an extension of the jaw, and can be used as anintroducer to pull the jaw into the patient anatomy, or otherwiseposition the jaw in a desired location within the patient. When theintroducing procedure is complete, the surgeon may remove the hemostatclamp, slip the rubber off of the jaw. The tubing slips off easilybecause the suture tension member is no longer clamped to the rubbertubing. As soon as the clamp is removed, the suture and rubber tubingbecome separate members. After the ablation procedure is complete, thejaw member can be withdrawn from the patient, pulling along theuntensioned suture. In this way, it is possible to attach or detach thered rubber without having to manually grasp the jaw tip and proximalportion of the tubing so as to bring them together. It provides anefficient technique for introducing a clamp, for example when the lowerjaw is blind under the pulmonary veins. By providing an apertured endplug at the end of the jaw bone, it is possible to obtain an introducermechanism that can pull on the jawbone without pulling directly on theboot, which may in some instances lead to undue stress on the boot, orunwanted bending of the ablation electrode, thus causing an electricalproblem. In some instances, a surgeon may forego the use of a tensioningsuture member, and instead simply place a proximal end of the rubbertubing over a distal end of the lower jaw member, for example, and usethe tubing as an introducer. The surgeon may wish to take care that theproximal section of the tubing does not unduly cover the ablationelement or electrode, particularly if the tubing is to be left in placeduring the ablation procedure. The distal section of the tubing can bemanually placed under the vessels, and the surgeon can use their fingersto ensure the tubing is being advanced along the appropriate insertionpath. During this insertion procedure, the tubing may be pulled at anangle so that it does not come off the jaw tip. Once the ablation clampis suitably positioned, the rubber tubing may be slipped off the jawtip, for example by pulling the tubing in a direction coaxial with thedistal jaw tip. In some instances, a surgeon may wish to place aproximal section of the tubing over a distal tip of the jaw, and thenstitch a suture through the side of the tubing and into the holes of theapertured end plug. In this way, the tubing can be fixedly attached withthe end plug or jawbone.

In some instances, there may be no end plug at the distal end of the jawtip. In some instances, the jawbone provides a rounded distal endwithout such an end plug. Optionally, a boot may cover the distal end ofthe jawbone. The boot may present a rounded distal end. Optionally, aboot may present a tapered or bullet shaped distal end. In use, thesurgeon may slip a proximal portion of the introducer rubber tubing overa distal section of the boot. In some instances, the surgeon may wish tostitch a suture through the rubber tubing and the boot, or otherwiseattach them with each other in another suitable manner. Hence, thetubing can be used to pull the jaw into place.

In some instances, the jaw may or may not include an end plug, and theboot may have a small hole or aperture at its distal end, for example asthe default result of a manufacturing procedure. A small soft plug maybe placed in the hole, and optionally glued therein, so that there is nosurface discontinuity along the boot. The plug and the boot can beconstructed of the same or similar materials. In some instances, theplug may include a light mechanism, optionally coupled with wires thatrun along a hollow core of the jawbone and into an interior of the clamphandle or shaft. When advancing the clamp mechanism within the patient'sbody, for example beneath the pulmonary veins, the surgeon may use thelight to help determine the location of the distal end of the clamp jawwithin the patient's anatomy. As an another example, it is known thatthe pericardium wraps around the heart and reflects or attaches onto theinner surface of the thoracic cavity in various places. When pushingthrough these reflections with the clamp device, the surgeon can rely onlight from the end plug lamp to determine the progress of the clamp asit goes through the tissue. For example, the light becomes brighter asthe distal jawtip is closer to breaking through the tissue orreflection. In some instances, the end plug lamp includes a distallylocated light emitting diode (LED). In some instances, the end pluglight mechanism includes a fiber optic member that faces outward fromthe distal portion of the jaw. Hence, a light source or lamp can belocated in the handle or elsewhere on the clamp device, and the fiberoptic member can operate to transmit light from the light source to theend of the distal jaw tip and out of the distal boot aperture. In someinstances, the ablation assembly may include a separable and reusableflashlight which can clip into or otherwise attach with the handle.

In some instances, the boot or end plug includes an elongate distalflexible member which can operate as an integrated introducer. Thesurgeon can use this long introducer lead to help position the clamp jawwithin the patient's anatomy. Once the ablation clamp is positioned asdesired, ablation may commence. The elongate distal section may be leftin the surgical field during the ablation. Optionally, the surgeon maywish to cut or sever the elongate distal flexible extension, forexample, by cutting the boot with scissors, prior to ablation.

In some instances, the end plug may include a port or aperture fordelivering a flush or irrigation fluid to the surgical site or patienttissue. For example, during some procedures blood or fluid may collectin the pericardial basin where the heart sits. The surgeon can use theapertured end plug to flush out this area, for example by using water orother suitable fluids. In some cases, the end plug may include a nozzletip. In some instances, ablation devices may include irrigation or waterports disposed at the surface of the electrodes. Optionally, exemplaryablation devices may include internal cooling mechanisms. For example,an ablation device may include an internal tube or passage positionedwithin a jawbone. Fluid may be expelled from a distal section of tubeand into the interior core of jawbone. Device includes a boot, an endplug, and electrode. As shown here, the tube floats inside of thejawbone, and terminates just proximal to the end plug. The tube can beused to pump out saline or other fluid, which is then circulated withinthe jawbone. The jawbone, which may be constructed of metal, can assumeor approach the temperature of the fluid. During an ablation, thetemperature of the boot may increase and the jawbone may also increasein temperature due to the burning or heating of the tissue. Thecirculated fluid can operate to carry heat away from the boot.

In some cases, the electrode is attached with the boot via legs locatedat the apex of each curve along the serpentine member. The legs canpenetrate directly into the boot at about a 90 degree angle from theelectrode plane. That is, the legs can be bent at a 90 degree angle fromthe flat surface of the electrode. The tips of each leg may have aswelled diameter. In some instances, the leg tips include an anchormechanism that helps hold the electrode securely against the boot. Forexample, the leg tips may include a “T” shape, which effectivelyprevents the electrode from popping out of or away from the boot,particularly when the boot is twisted or otherwise deformed. This “T”anchor or foot of the leg tip can be embedded within the boot, below theboot surface. Hence, a significant amount of force is required to pullthe electrode out of the boot. In some instances, the boot includes ananti-torsional mechanism. For example, the boot may include an internaltubular or coiled structure that can flex from side to side and alsoprovide torsional rigidity. In some devices, a polymer sleeve may beplaced over the jawbone, between the jawbone and the boot, providing alubricious intermediary between the jawbone and boot.

Individual system elements or aspects of a tissue treatment computersystem may be implemented in a separated or more integrated manner. Insome embodiments treatment systems, which may include computer systems,also include software elements, for example located within a workingmemory of a memory, including an operating system and other code, suchas a program designed to implement method embodiments of the presentinvention. In some cases, software modules implementing thefunctionality of the methods as described herein, may be stored in astorage subsystem. It is appreciated that systems can be configured tocarry out various method aspects described herein. Each of the devicesor modules of the present invention can include software modules on acomputer readable medium that is processed by a processor, hardwaremodules, or any combination thereof. Any of a variety of commonly usedplatforms, such as Windows, MacIntosh, and UNIX, along with any of avariety of commonly used programming languages, such as C or C++, may beused to implement embodiments of the present invention. In some cases,tissue treatment systems include FDA validated operating systems orsoftware/hardware modules suitable for use in medical devices. Tissuetreatment systems can also include multiple operating systems. Forexample, a tissue treatment system can include a FDA validated operatingsystem for safety critical operations performed by the treatment system,such as data input, power control, diagnostic procedures, recording,decision making, and the like. A tissue treatment system can alsoinclude a non-validated operating system for less critical operations.In some embodiments, a computer system can be in integrated into atissue treatment system, and in some embodiments, a computer system canbe separate from, but in connectivity with, a tissue treatment system.It will be apparent to those skilled in the art that substantialvariations may be used in accordance with any specific requirements. Forexample, customized hardware might also be used and/or particularelements might be implemented in hardware, software (including portablesoftware, such as applets), or both. Further, connection to othercomputing devices such as network input/output devices may be employed.Relatedly, any of the hardware and software components discussed hereincan be integrated with or configured to interface with other medicaltreatment or information systems used at other locations.

According to some embodiments, the treatment systems and methodsdescribed herein may be used in conjunction or combined with aspects ofintroducer systems and methods such as those described in U.S. PatentApplication Nos. 60/337,070 filed Dec. 4, 2001; Ser. No. 10/272,446filed Oct. 15, 2002; Ser. No. 10/310,675 filed Dec. 4, 2002; Ser. No.10/410,618 filed Apr. 8, 2003; Ser. No. 11/148,611 filed Jun. 8, 2005;60/939,201 filed May 21, 2007; 61/015,472 filed Dec. 20, 2007;61/051,975, filed May 9, 2008; Ser. No. 12/124,743 filed May 21, 2008;Ser. No. 12/124,766 filed May 21, 2008; Ser. No. 12/255,076 filed Oct.21, 2008; Ser. No. 12/273,938 filed Nov. 19, 2008; Ser. No. 12/339,331filed Dec. 19, 2008; Ser. No. 12/463,760 filed May 11, 2009; 61/179,564filed May 19, 2009; 61/231,613 filed Aug. 5, 2009; and 61/241,297 filedSep. 10, 2009. The entire content of each of these filings isincorporated herein by reference for all purposes.

Relatedly, in some instances, the treatment systems and methodsdescribed herein may include elements or aspects of the medical systemsand methods discussed in U.S. Patent Application Nos. 60/337,070 filedDec. 4, 2001; Ser. No. 10/080,374 filed Feb. 19, 2002; Ser. No.10/255,025 filed Sep. 24, 2002; Ser. No. 10/272,446 filed Oct. 15, 2002;Ser. No. 10/310,675 filed Dec. 4, 2002; Ser. No. 10/410,618 filed Apr.8, 2003; Ser. No. 11/067,535 filed Feb. 25, 2005; Ser. No. 11/148,611filed Jun. 8, 2005; 60/939,201 filed May 21, 2007; 61/015,472 filed Dec.20, 2007; 61/051,975, filed May 9, 2008; Ser. No. 12/124,743 filed May21, 2008; Ser. No. 12/124,766 filed May 21, 2008; Ser. No. 12/255,076filed Oct. 21, 2008; Ser. No. 12/273,938 filed Nov. 19, 2008; Ser. No.12/339,331 filed Dec. 19, 2008; Ser. No. 12/463,760 filed May 11, 2009;61/179,564 filed May 19, 2009; 61/231,613 filed Aug. 5, 2009; and61/241,297 filed Sep. 10, 2009. The entire content of each of thesefilings is incorporated herein by reference for all purposes.

Different arrangements of the components depicted in the drawings ordescribed above, as well as components and steps not shown or describedare possible. Similarly, some features and subcombinations are usefuland may be employed without reference to other features andsubcombinations. Embodiments of the invention have been described forillustrative and not restrictive purposes, and alternative embodimentswill become apparent to readers of this patent. Accordingly, the presentinvention is not limited to the embodiments described above or depictedin the drawings, and various embodiments and modifications can be madewithout departing from the scope of the claims below.

While exemplary embodiments have been described in some detail, by wayof example and for clarity of understanding, those of skill in the artwill recognize that a variety of modification, adaptations, and changesmay be employed. Hence, the scope of the present invention should belimited solely by the claims.

What is claimed is:
 1. A surgical system for administering a lesionforming treatment to a patient tissue, comprising: a suction mechanismdefining an inner recess; and a lesion forming mechanism disposed withinthe inner recess defined by the suction mechanism, wherein the suctionmechanism is reinforced to resist collapse when a vacuum is presentwithin the inner recess, and wherein the inner recess is configured toreceive a curvilinear portion of the tissue for administration of thelesion forming treatment thereto.
 2. The surgical system according toclaim 1, wherein the curvilinear portion of patient tissue comprises asection having a thickness T, and wherein the inner recess defined bythe suction mechanism is configured to receive the section therein, suchthat the section extends into the inner recess at a distance of greaterthan 0.5 T.
 3. The surgical system according to claim 1, wherein thesuction mechanism comprises a pod assembly housing a ribcage mechanism,and the ribcage mechanism operates to reinforce the suction mechanism sothat the suction mechanism resists collapse when a vacuum is presentwithin the inner recess.
 4. The surgical system according to claim 3,wherein the suction mechanism is configured to deliver suction to aportion of the patient tissue, so as to draw the portion of the patienttissue into an inner recess defined by the ribcage mechanism, and intoproximity with the lesion forming mechanism.
 5. The surgical systemaccording to claim 1, wherein the lesion forming mechanism comprises amember selected from the group consisting of a bipolar radiofrequencyenergy ablation mechanism, a monopolar radiofrequency energy ablationmechanism, a high voltage pulse mechanism, a microwave energy mechanism,an infrared laser mechanism, a cryo-thermal mechanism, an ultrasoundablation mechanism, a chemical ablation mechanism, and a radiationmechanism.
 6. The surgical system according to claim 1, wherein thelesion forming mechanism comprises a ribcage mechanism, and the ribcagemechanism operates to reinforce the suction mechanism so that thesuction mechanism resists collapse when a vacuum is present within theinner recess.
 7. The surgical system according to claim 1, wherein thesuction mechanism comprises a pocket that channels a vacuum delivered bythe suction mechanism.
 8. The surgical system according to claim 1,further comprising a temperature sensor disposed along a central portionof the inner recess.
 9. The surgical system according to claim 1,wherein the suction mechanism comprises a cooling lumen.
 10. Thesurgical system according to claim 1, wherein the suction mechanismcomprises an irrigation lumen.
 11. A surgical system for administering alesion forming treatment to a patient tissue, comprising: a stabilizermechanism defining an inner recess; and a lesion forming mechanismdisposed within the inner recess of the stabilizer mechanism.
 12. Thesurgical system according to claim 11, wherein the stabilizer mechanismcomprises a pod assembly housing a ribcage mechanism.
 13. The surgicalsystem according to claim 12, wherein the ribcage mechanism defines aninner recess configured to receive a portion of the patient tissue, andwherein the lesion forming mechanism is disposed within the inner recessdefined by the ribcage mechanism, the lesion forming mechanismconfigured to transmit the lesion forming treatment to the portion ofthe patient tissue.
 14. The surgical system according to claim 12,wherein the flexible stabilizer mechanism is configured to deliversuction to a portion of the patient tissue, so as to draw the portion ofthe patient tissue into an inner recess defined by the ribcagemechanism, and into proximity with the lesion forming mechanism.
 15. Thesurgical system according to claim 11, wherein the lesion formingmechanism comprises a ribcage mechanism.
 16. The surgical systemaccording to claim 11, wherein the lesion forming mechanism comprises amember selected from the group consisting of a bipolar radiofrequencyenergy ablation mechanism, a monopolar radiofrequency energy ablationmechanism, a high voltage pulse mechanism, a microwave energy mechanism,an infrared laser mechanism, a cryo-thermal mechanism, an ultrasoundablation mechanism, a chemical ablation mechanism, and a radiationmechanism.
 17. The surgical system according to claim 11, wherein thestabilizer mechanism comprises a pocket that channels a vacuum deliveredby the stabilizer mechanism.
 18. The surgical system according to claim11, further comprising a temperature sensor disposed along a centralportion of the ribcage mechanism inner recess.
 19. The surgical systemaccording to claim 11, wherein the stabilizer mechanism comprises acooling lumen.
 20. The surgical system according to claim 11, whereinthe stabilizer mechanism comprises an irrigation lumen.